diff --git a/build/genie/genie.lua b/build/genie/genie.lua
index 49c69b09..025b4b48 100644
--- a/build/genie/genie.lua
+++ b/build/genie/genie.lua
@@ -21,7 +21,7 @@ project "xlnt.test"
        "../../tests/runner-autogen.cpp"
     }
     links { "xlnt", "miniz" }
-    prebuildcommands { "../generate-tests.sh" }
+    prebuildcommands { "../../generate-tests.sh" }
     flags { "Unicode" }
     configuration "windows"
         defines { "WIN32" }
diff --git a/include/xlnt/s11n/excel_serializer.hpp b/include/xlnt/s11n/excel_serializer.hpp
index 3eb4628f..d52ba22d 100644
--- a/include/xlnt/s11n/excel_serializer.hpp
+++ b/include/xlnt/s11n/excel_serializer.hpp
@@ -37,7 +37,7 @@ class workbook;
 class excel_serializer
 {
 public:
-    static std::string central_directory_signature();
+    static const std::string central_directory_signature();
     static std::string repair_central_directory(const std::string &original);
     
     excel_serializer(workbook &wb);
@@ -46,9 +46,9 @@ public:
     bool load_stream_workbook(std::istream &stream, bool guess_types = false, bool data_only = false);
     bool load_virtual_workbook(const std::vector<std::uint8_t> &bytes, bool guess_types = false, bool data_only = false);
     
-    bool save_workbook(workbook &wb, const std::string &filename, bool as_template = false);
-    bool save_virtual_workbook(xlnt::workbook &wb, std::vector<std::uint8_t> &bytes, bool as_template = false);
-    bool save_stream_workbook(xlnt::workbook &wb, std::ostream &stream, bool as_template = false);
+    bool save_workbook(const std::string &filename, bool as_template = false);
+    bool save_virtual_workbook(std::vector<std::uint8_t> &bytes, bool as_template = false);
+    bool save_stream_workbook(std::ostream &stream, bool as_template = false);
     
 private:
     void read_data(bool guess_types, bool data_only);
diff --git a/include/xlnt/s11n/manifest_serializer.hpp b/include/xlnt/s11n/manifest_serializer.hpp
index 41697c89..5babe4af 100644
--- a/include/xlnt/s11n/manifest_serializer.hpp
+++ b/include/xlnt/s11n/manifest_serializer.hpp
@@ -14,7 +14,7 @@ class manifest_serializer
 public:
     manifest_serializer(manifest &m);
     
-    bool read_mainfest(const xml_document &xml);
+    bool read_manifest(const xml_document &xml);
     bool write_manifest(xml_document &xml);
     
 private:
diff --git a/include/xlnt/s11n/relationship_serializer.hpp b/include/xlnt/s11n/relationship_serializer.hpp
index 8df03c90..2bd3996e 100644
--- a/include/xlnt/s11n/relationship_serializer.hpp
+++ b/include/xlnt/s11n/relationship_serializer.hpp
@@ -10,8 +10,9 @@ class xml_document;
 
 class relationship_serializer
 {
-    bool read_relationships(const xml_document &xml, const std::string &dir, std::vector<relationship> &relationships);
-    bool write_relationships(const std::vector<relationship> &relationships, const std::string &dir, xml_document &xml);
+public:
+    static bool read_relationships(const xml_document &xml, const std::string &dir, std::vector<relationship> &relationships);
+    static bool write_relationships(const std::vector<relationship> &relationships, const std::string &dir, xml_document &xml);
 };
     
 } // namespace xlnt
diff --git a/include/xlnt/s11n/theme_serializer.hpp b/include/xlnt/s11n/theme_serializer.hpp
index 6db65bc5..6cb9803c 100644
--- a/include/xlnt/s11n/theme_serializer.hpp
+++ b/include/xlnt/s11n/theme_serializer.hpp
@@ -26,11 +26,14 @@
 #include <string>
 
 namespace xlnt {
+    
+class theme;
+class xml_document;
 
 class theme_serializer
 {
 public:
-    theme read_theme(const xml_document &xml);
+    //theme read_theme(const xml_document &xml);
     xml_document write_theme(const theme &theme_);
 };
 
diff --git a/include/xlnt/s11n/workbook_serializer.hpp b/include/xlnt/s11n/workbook_serializer.hpp
index 1400d18e..54311811 100644
--- a/include/xlnt/s11n/workbook_serializer.hpp
+++ b/include/xlnt/s11n/workbook_serializer.hpp
@@ -35,10 +35,14 @@ class worksheet;
 class workbook;
 class zip_file;
 class xml_document;
+class xml_node;
     
 class workbook_serializer
 {
 public:
+    //TODO: does this go here?
+    static std::string determine_document_type(const manifest &manifest_);
+    
     workbook_serializer(workbook &wb);
     
     void read_workbook(const xml_document &xml);
@@ -48,17 +52,14 @@ public:
     xml_document write_workbook() const;
     xml_document write_properties_app() const;
     xml_document write_properties_core() const;
-    
+
 private:
-    //workbook_view, sheets, sheet, defined_names
-    std::string determine_document_type(const manifest &manifest_);
-    
     using string_pair = std::pair<std::string, std::string>;
     
     std::vector<string_pair> read_sheets(zip_file &archive);
     std::vector<string_pair> detect_worksheets(zip_file &archive);
 
-    std::string write_defined_names(const workbook &wb);
+    bool write_named_ranges(xml_node &named_ranges_node);
     
     workbook &wb_;
 };
diff --git a/include/xlnt/s11n/worksheet_serializer.hpp b/include/xlnt/s11n/worksheet_serializer.hpp
index 31eacd34..0beb0ba7 100644
--- a/include/xlnt/s11n/worksheet_serializer.hpp
+++ b/include/xlnt/s11n/worksheet_serializer.hpp
@@ -41,9 +41,8 @@ class worksheet_serializer
 public:
     worksheet_serializer(worksheet sheet);
     
-    bool read_worksheet(const xml_document &xml, const std::vector<std::string> &shared_strings, const relationship &rel,  worksheet ws);
-    std::string read_dimension(const xml_node &dimension_node);
-    bool write_worksheet(const worksheet ws, const std::vector<std::string> &string_table, xml_document &xml);
+    bool read_worksheet(const xml_document &xml, const std::vector<std::string> &shared_strings, const relationship &rel);
+    bool write_worksheet(const std::vector<std::string> &string_table, xml_document &xml);
     
 private:
     worksheet sheet_;
diff --git a/include/xlnt/s11n/xml_node.hpp b/include/xlnt/s11n/xml_node.hpp
index 8534b084..f35741b4 100644
--- a/include/xlnt/s11n/xml_node.hpp
+++ b/include/xlnt/s11n/xml_node.hpp
@@ -22,6 +22,7 @@ public:
     
     const std::vector<xml_node> &get_children() const;
     bool has_child(const std::string &child_name) const;
+    xml_node &get_child(const std::string &child_name);
     const xml_node &get_child(const std::string &child_name) const;
     xml_node &add_child(const xml_node &child);
     xml_node &add_child(const std::string &child_name);
diff --git a/include/xlnt/styles/font.hpp b/include/xlnt/styles/font.hpp
index 7b471bbd..bf64c683 100644
--- a/include/xlnt/styles/font.hpp
+++ b/include/xlnt/styles/font.hpp
@@ -70,6 +70,8 @@ public:
     color get_color() const { return color_; }
     
     bool has_family() const { return has_family_; }
+    int get_family() const { return family_; }
+    
     bool has_scheme() const { return has_scheme_; }
     
     std::size_t hash() const
diff --git a/include/xlnt/styles/side.hpp b/include/xlnt/styles/side.hpp
index 4d4cb5ac..4939b8d8 100644
--- a/include/xlnt/styles/side.hpp
+++ b/include/xlnt/styles/side.hpp
@@ -50,12 +50,6 @@ enum class border_style
 class side
 {
 public:
-    enum class color_type
-    {
-        theme,
-        indexed
-    };
-    
     side();
     
     std::size_t hash() const
diff --git a/include/xlnt/workbook/workbook.hpp b/include/xlnt/workbook/workbook.hpp
index c5ea9518..6542566e 100644
--- a/include/xlnt/workbook/workbook.hpp
+++ b/include/xlnt/workbook/workbook.hpp
@@ -49,6 +49,7 @@ class range;
 class range_reference;
 class relationship;
 class style;
+class theme;
 class worksheet;
 class zip_file;
     
@@ -199,7 +200,7 @@ public:
     
 	void create_relationship(const std::string &id, const std::string &target, relationship::type type);
 	relationship get_relationship(const std::string &id) const;
-    std::vector<relationship> get_relationships() const;
+    const std::vector<relationship> &get_relationships() const;
     
     void add_alignment(const alignment &a);
     void add_border(const border &b);
@@ -237,8 +238,8 @@ public:
     
     void set_code_name(const std::string &code_name);
     
-    bool has_loaded_theme();
-    std::string get_loaded_theme();
+    bool has_loaded_theme() const;
+    const theme &get_loaded_theme() const;
     
     const style &get_style(std::size_t style_id) const;
     std::size_t add_style(const style &style_);
@@ -246,6 +247,8 @@ public:
     manifest &get_manifest();
     const manifest &get_manifest() const;
     
+    const std::vector<relationship> &get_root_relationships() const;
+        
 private:
     friend class worksheet;
     std::shared_ptr<detail::workbook_impl> d_;
diff --git a/include/xlnt/worksheet/worksheet.hpp b/include/xlnt/worksheet/worksheet.hpp
index 9be5f5a5..13655035 100644
--- a/include/xlnt/worksheet/worksheet.hpp
+++ b/include/xlnt/worksheet/worksheet.hpp
@@ -223,7 +223,7 @@ public:
     
     // relationships
     relationship create_relationship(relationship::type type, const std::string &target_uri);
-    std::vector<relationship> get_relationships();
+    const std::vector<relationship> &get_relationships() const;
     
     // charts
     //void add_chart(chart chart);
@@ -262,7 +262,9 @@ public:
     const range operator()(const cell_reference &top_left, const cell_reference &bottom_right) const;
     
     // page
+    page_setup &get_page_setup();
     const page_setup &get_page_setup() const;
+    margins &get_page_margins();
     const margins &get_page_margins() const;
     
     // auto filter
diff --git a/include/xlnt/xlnt.hpp b/include/xlnt/xlnt.hpp
index 8343e044..39d2f4ed 100644
--- a/include/xlnt/xlnt.hpp
+++ b/include/xlnt/xlnt.hpp
@@ -42,11 +42,9 @@ const std::string download_url = "https://github.com/tfussell/xlnt/archive/maste
 #include "common/relationship.hpp"
 #include "common/string_table.hpp"
 #include "common/zip_file.hpp"
-#include "reader/excel_reader.hpp"
 #include "workbook/document_properties.hpp"
 #include "workbook/named_range.hpp"
 #include "workbook/workbook.hpp"
 #include "worksheet/range.hpp"
 #include "worksheet/range_reference.hpp"
 #include "worksheet/worksheet.hpp"
-#include "writer/workbook_writer.hpp"
diff --git a/source/detail/workbook_impl.hpp b/source/detail/workbook_impl.hpp
index 9ba12776..509dee9b 100644
--- a/source/detail/workbook_impl.hpp
+++ b/source/detail/workbook_impl.hpp
@@ -13,7 +13,8 @@ struct workbook_impl
     workbook_impl(const workbook_impl &other) 
         : active_sheet_index_(other.active_sheet_index_),
         worksheets_(other.worksheets_), 
-        relationships_(other.relationships_), 
+        relationships_(other.relationships_),
+        root_relationships_(other.root_relationships_),
         drawings_(other.drawings_), 
         properties_(other.properties_), 
         guess_types_(other.guess_types_),
@@ -35,6 +36,8 @@ struct workbook_impl
         std::copy(other.worksheets_.begin(), other.worksheets_.end(), back_inserter(worksheets_));
         relationships_.clear();
         std::copy(other.relationships_.begin(), other.relationships_.end(), std::back_inserter(relationships_));
+        root_relationships_.clear();
+        std::copy(other.root_relationships_.begin(), other.root_relationships_.end(), std::back_inserter(root_relationships_));
         drawings_.clear();
         std::copy(other.drawings_.begin(), other.drawings_.end(), back_inserter(drawings_));
         properties_ = other.properties_;
@@ -54,6 +57,7 @@ struct workbook_impl
     std::size_t active_sheet_index_;
     std::vector<worksheet_impl> worksheets_;
     std::vector<relationship> relationships_;
+    std::vector<relationship> root_relationships_;
     std::vector<drawing> drawings_;
     
     document_properties properties_;
@@ -72,6 +76,8 @@ struct workbook_impl
     std::vector<number_format> number_formats_;
     
     manifest manifest_;
+    
+    theme theme_;
 };
 
 } // namespace detail
diff --git a/source/s11n/excel_serializer.cpp b/source/s11n/excel_serializer.cpp
index ada9b873..f57b99ed 100644
--- a/source/s11n/excel_serializer.cpp
+++ b/source/s11n/excel_serializer.cpp
@@ -1,7 +1,20 @@
 #include <xlnt/s11n/excel_serializer.hpp>
+#include <xlnt/common/exceptions.hpp>
 #include <xlnt/s11n/manifest_serializer.hpp>
+#include <xlnt/s11n/relationship_serializer.hpp>
+#include <xlnt/s11n/shared_strings_serializer.hpp>
+#include <xlnt/s11n/style_serializer.hpp>
+#include <xlnt/s11n/theme_serializer.hpp>
+#include <xlnt/s11n/workbook_serializer.hpp>
+#include <xlnt/s11n/worksheet_serializer.hpp>
+#include <xlnt/s11n/xml_document.hpp>
+#include <xlnt/s11n/xml_serializer.hpp>
+#include <xlnt/workbook/document_properties.hpp>
 #include <xlnt/workbook/manifest.hpp>
 #include <xlnt/workbook/workbook.hpp>
+#include <xlnt/worksheet/worksheet.hpp>
+
+#include <detail/constants.hpp>
 
 namespace {
     
@@ -22,99 +35,69 @@ std::string::size_type find_string_in_string(const std::string &string, const st
     return possible_match_index;
 }
 
-xlnt::workbook load_workbook(xlnt::zip_file &archive, bool guess_types, bool data_only)
+bool load_workbook(xlnt::zip_file &archive, bool guess_types, bool data_only, xlnt::workbook &wb)
 {
-    xlnt::workbook wb;
-    
     wb.set_guess_types(guess_types);
     wb.set_data_only(data_only);
     
-    auto content_types = xlnt::read_content_types(archive);
-    auto type = xlnt::determine_document_type(content_types);
+    xlnt::manifest_serializer ms(wb.get_manifest());
+    ms.read_manifest(xlnt::xml_serializer::deserialize(archive.read(xlnt::constants::ArcContentTypes)));
     
-    if(type != "excel")
+    if(xlnt::workbook_serializer::determine_document_type(wb.get_manifest()) != "excel")
     {
         throw xlnt::invalid_file_exception("");
     }
     
     wb.clear();
     
-    auto workbook_relationships = read_relationships(archive, "xl/workbook.xml");
+    std::vector<xlnt::relationship> workbook_relationships;
+    xlnt::relationship_serializer::read_relationships(xlnt::xml_serializer::deserialize(archive.read("xl/_rels/workbook.xml.rels")), "", workbook_relationships);
     
     for(auto relationship : workbook_relationships)
     {
         wb.create_relationship(relationship.get_id(), relationship.get_target_uri(), relationship.get_type());
     }
     
-    pugi::xml_document doc;
-    doc.load(archive.read("xl/workbook.xml").c_str());
+    auto xml = xlnt::xml_serializer::deserialize(archive.read(xlnt::constants::ArcWorkbook));
     
-    auto root_node = doc.child("workbook");
+    auto &root_node = xml.root();
     
-    auto workbook_pr_node = root_node.child("workbookPr");
-    wb.get_properties().excel_base_date = (workbook_pr_node.attribute("date1904") != nullptr && workbook_pr_node.attribute("date1904").as_int() != 0) ? xlnt::calendar::mac_1904 : xlnt::calendar::windows_1900;
+    auto &workbook_pr_node = root_node.get_child("workbookPr");
+    wb.get_properties().excel_base_date = (workbook_pr_node.has_attribute("date1904") && workbook_pr_node.get_attribute("date1904") != "0") ? xlnt::calendar::mac_1904 : xlnt::calendar::windows_1900;
     
-    auto sheets_node = root_node.child("sheets");
+    xlnt::shared_strings_serializer shared_strings_serializer_;
+    std::vector<std::string> shared_strings;
+    shared_strings_serializer_.read_strings(xlnt::xml_serializer::deserialize(archive.read(xlnt::constants::ArcSharedString)), shared_strings);
     
-    xlnt::shared_strings_reader shared_strings_reader_;
-    auto shared_strings = shared_strings_reader_.read_strings(archive);
+    xlnt::style_serializer style_reader_(wb);
+    style_reader_.read_stylesheet(xlnt::xml_serializer::deserialize(archive.read(xlnt::constants::ArcStyles)));
     
-    xlnt::style_reader style_reader_(wb);
-    style_reader_.read_styles(archive);
+    auto &sheets_node = root_node.get_child("sheets");
     
-    for(const auto &border_ : style_reader_.get_borders())
+    for(auto sheet_node : sheets_node.get_children())
     {
-        wb.add_border(border_);
-    }
-    
-    for(const auto &fill_ : style_reader_.get_fills())
-    {
-        wb.add_fill(fill_);
-    }
-    
-    for(const auto &font_ : style_reader_.get_fonts())
-    {
-        wb.add_font(font_);
-    }
-    
-    for(const auto &number_format_ : style_reader_.get_number_formats())
-    {
-        wb.add_number_format(number_format_);
-    }
-    
-    for(auto &color_rgb : style_reader_.get_colors())
-    {
-        wb.add_color(xlnt::color(xlnt::color::type::rgb, color_rgb));
-    }
-    
-    for(const auto &style : style_reader_.get_styles())
-    {
-        wb.add_style(style);
-    }
-    
-    for(auto sheet_node : sheets_node.children("sheet"))
-    {
-        auto rel = wb.get_relationship(sheet_node.attribute("r:id").as_string());
-        auto ws = wb.create_sheet(sheet_node.attribute("name").as_string(), rel);
+        auto rel = wb.get_relationship(sheet_node.get_attribute("r:id"));
+        auto ws = wb.create_sheet(sheet_node.get_attribute("name"), rel);
         
-        xlnt::read_worksheet(ws, archive, rel, shared_strings);
+        xlnt::worksheet_serializer worksheet_serializer(ws);
+        worksheet_serializer.read_worksheet(xlnt::xml_serializer::deserialize(archive.read(rel.get_target_uri())), shared_strings, rel);
     }
     
-    return wb;
+    return true;
 }
     
 } // namespace
 
 namespace xlnt {
 
-std::string excel_reader::CentralDirectorySignature()
+const std::string excel_serializer::central_directory_signature()
 {
     return "\x50\x4b\x05\x06";
 }
 
-std::string excel_reader::repair_central_directory(const std::string &original)
+std::string excel_serializer::repair_central_directory(const std::string &original)
 {
-    auto pos = find_string_in_string(original, CentralDirectorySignature());
+    auto pos = find_string_in_string(original, central_directory_signature());
     
     if(pos != std::string::npos)
     {
@@ -124,104 +107,76 @@ std::string excel_reader::repair_central_directory(const std::string &original)
     return original;
 }
 
-workbook excel_reader::load_workbook(std::istream &stream, bool guess_types, bool data_only)
+bool excel_serializer::load_stream_workbook(std::istream &stream, bool guess_types, bool data_only)
 {
     std::vector<std::uint8_t> bytes((std::istream_iterator<char>(stream)),
                                     std::istream_iterator<char>());
-    
-    return load_workbook(bytes, guess_types, data_only);
+
+    return load_virtual_workbook(bytes, guess_types, data_only);
 }
 
-workbook excel_reader::load_workbook(const std::string &filename, bool guess_types, bool data_only)
+bool excel_serializer::load_workbook(const std::string &filename, bool guess_types, bool data_only)
 {
-    xlnt::zip_file archive;
-    
     try
     {
-        archive.load(filename);
+        archive_.load(filename);
     }
     catch(std::runtime_error)
     {
         throw invalid_file_exception(filename);
     }
     
-    return ::load_workbook(archive, guess_types, data_only);
+    return ::load_workbook(archive_, guess_types, data_only, wb_);
 }
 
-xlnt::workbook excel_reader::load_workbook(const std::vector<std::uint8_t> &bytes, bool guess_types, bool data_only)
+bool excel_serializer::load_virtual_workbook(const std::vector<std::uint8_t> &bytes, bool guess_types, bool data_only)
 {
-    xlnt::zip_file archive;
-    archive.load(bytes);
+    archive_.load(bytes);
     
-    return ::load_workbook(archive, guess_types, data_only);
+    return ::load_workbook(archive_, guess_types, data_only, wb_);
 }
     
-excel_writer::excel_writer(workbook &wb) : wb_(wb)
+excel_serializer::excel_serializer(workbook &wb) : wb_(wb)
 {
 }
 
-void excel_writer::save(const std::string &filename, bool as_template)
+void excel_serializer::write_data(bool as_template)
 {
-    zip_file archive;
-    write_data(archive, as_template);
-    archive.save(filename);
+    relationship_serializer relationship_serializer_;
+    
+    xlnt::xml_document root_rels_xml;
+    relationship_serializer_.write_relationships(wb_.get_root_relationships(), "", root_rels_xml);
+    archive_.writestr(constants::ArcRootRels, xml_serializer::serialize(root_rels_xml));
+    
+    xml_document workbook_rels_xml;
+    relationship_serializer_.write_relationships(wb_.get_relationships(), "", workbook_rels_xml);
+    archive_.writestr(constants::ArcWorkbookRels, xml_serializer::serialize(workbook_rels_xml));
+    
+    xml_document properties_app_xml;
+    workbook_serializer workbook_serializer_(wb_);
+    archive_.writestr(constants::ArcApp, xml_serializer::serialize(workbook_serializer_.write_properties_app()));
+    archive_.writestr(constants::ArcCore, xml_serializer::serialize(workbook_serializer_.write_properties_core()));
+    
+    theme_serializer theme_serializer_;
+    xml_document theme_xml = theme_serializer_.write_theme(wb_.get_loaded_theme());
+    archive_.writestr(constants::ArcTheme, xml_serializer::serialize(theme_xml));
+    
+    archive_.writestr(constants::ArcWorkbook, xml_serializer::serialize(workbook_serializer_.write_workbook()));
+    
+    style_serializer style_serializer_(wb_);
+    xml_document style_xml;
+    style_serializer_.write_stylesheet(style_xml);
+    archive_.writestr(constants::ArcStyles, xml_serializer::serialize(style_xml));
+    
+    manifest_serializer manifest_serializer_(wb_.get_manifest());
+    xml_document manifest_xml;
+    manifest_serializer_.write_manifest(manifest_xml);
+    archive_.writestr(constants::ArcContentTypes, xml_serializer::serialize(manifest_xml));
+    
+    write_worksheets();
 }
 
-void excel_writer::write_data(zip_file &archive, bool as_template)
-{
-    archive.writestr(constants::ArcRootRels, write_root_rels(wb_));
-    archive.writestr(constants::ArcWorkbookRels, write_workbook_rels(wb_));
-    archive.writestr(constants::ArcApp, write_properties_app(wb_));
-    archive.writestr(constants::ArcCore, write_properties_core(wb_.get_properties()));
-    
-    if(wb_.has_loaded_theme())
-    {
-        archive.writestr(constants::ArcTheme, wb_.get_loaded_theme());
-    }
-    else
-    {
-        archive.writestr(constants::ArcTheme, write_theme());
-    }
-    
-    archive.writestr(constants::ArcWorkbook, write_workbook(wb_));
-    
-    auto shared_strings = extract_all_strings(wb_);
-    
-    write_charts(archive);
-    write_images(archive);
-    write_shared_strings(archive, shared_strings);
-    write_worksheets(archive, shared_strings);
-    write_chartsheets(archive);
-    write_external_links(archive);
-    
-    style_writer style_writer_(wb_);
-    archive.writestr(constants::ArcStyles, style_writer_.write_table());
-    
-    auto manifest = write_content_types(wb_, as_template);
-    archive.writestr(constants::ArcContentTypes, manifest);
-}
-
-void excel_writer::write_shared_strings(xlnt::zip_file &archive, const std::vector<std::string> &shared_strings)
-{
-    archive.writestr(constants::ArcSharedString, ::xlnt::write_shared_strings(shared_strings));
-}
-
-void excel_writer::write_images(zip_file &/*archive*/)
-{
-    
-}
-
-void excel_writer::write_charts(zip_file &/*archive*/)
-{
-    
-}
-
-void excel_writer::write_chartsheets(zip_file &/*archive*/)
-{
-    
-}
-
-void excel_writer::write_worksheets(zip_file &archive, const std::vector<std::string> &shared_strings)
+void excel_serializer::write_worksheets()
 {
     std::size_t index = 0;
     
@@ -232,7 +187,10 @@ void excel_writer::write_worksheets(zip_file &archive, const std::vector<std::st
             if(relationship.get_type() == relationship::type::worksheet &&
                workbook::index_from_ws_filename(relationship.get_target_uri()) == index)
             {
-                archive.writestr(relationship.get_target_uri(), write_worksheet(ws, shared_strings));
+                worksheet_serializer serializer_(ws);
+                xml_document xml;
+                serializer_.write_worksheet(shared_strings_, xml);
+                archive_.writestr(relationship.get_target_uri(),  xml_serializer::serialize(xml));
                 break;
             }
         }
@@ -241,27 +199,33 @@ void excel_writer::write_worksheets(zip_file &archive, const std::vector<std::st
     }
 }
 
-void excel_writer::write_external_links(zip_file &/*archive*/)
+void excel_serializer::write_external_links()
 {
     
 }
-
-bool save_workbook(workbook &wb, const std::string &filename, bool as_template)
+    
+bool excel_serializer::save_stream_workbook(std::ostream &stream, bool as_template)
 {
-    excel_writer writer(wb);
-    writer.save(filename, as_template);
+    write_data(as_template);
+    archive_.save(stream);
+    
     return true;
 }
 
-std::vector<std::uint8_t> save_virtual_workbook(xlnt::workbook &wb, bool as_template)
+bool excel_serializer::save_workbook(const std::string &filename, bool as_template)
 {
-    zip_file archive;
-    excel_writer writer(wb);
-    writer.write_data(archive, as_template);
-    std::vector<std::uint8_t> buffer;
-    archive.save(buffer);
+    write_data(as_template);
+    archive_.save(filename);
+
+    return true;
+}
+
+bool excel_serializer::save_virtual_workbook(std::vector<std::uint8_t> &bytes, bool as_template)
+{
+    write_data(as_template);
+    archive_.save(bytes);
     
-    return buffer;
+    return true;
 }
     
 } // namespace xlnt
diff --git a/source/s11n/relationship_serializer.cpp b/source/s11n/relationship_serializer.cpp
index 28ea0080..24a3304c 100644
--- a/source/s11n/relationship_serializer.cpp
+++ b/source/s11n/relationship_serializer.cpp
@@ -7,10 +7,27 @@
 #include "detail/constants.hpp"
 
 namespace xlnt {
-
+    
 bool relationship_serializer::read_relationships(const xml_document &xml, const std::string &dir, std::vector<relationship> &relationships)
 {
-    return false;
+    auto root_node = xml.root();
+    root_node.set_name("Relationships");
+    
+    for(auto relationship_node : root_node.get_children())
+    {
+        if(relationship_node.get_name() != "Relationship")
+        {
+            continue;
+        }
+        
+        std::string id = relationship_node.get_attribute("Id");
+        std::string type = relationship_node.get_attribute("Type");
+        std::string target = relationship_node.get_attribute("Target");
+        
+        relationships.push_back(xlnt::relationship(type, id, target));
+    }
+    
+    return true;
 }
     
 bool relationship_serializer::write_relationships(const std::vector<relationship> &relationships, const std::string &dir, xml_document &xml)
@@ -29,15 +46,15 @@ bool relationship_serializer::write_relationships(const std::vector<relationship
             target = target.substr(dir.size());
         }
         
-        auto app_props_node = root_node.add_child("Relationship");
+        auto relationship_node = root_node.add_child("Relationship");
         
-        app_props_node.add_attribute("Id", relationship.get_id());
-        app_props_node.add_attribute("Target", target);
-        app_props_node.add_attribute("Type", relationship.get_type_string());
+        relationship_node.add_attribute("Id", relationship.get_id());
+        relationship_node.add_attribute("Target", target);
+        relationship_node.add_attribute("Type", relationship.get_type_string());
         
         if(relationship.get_target_mode() == target_mode::external)
         {
-            app_props_node.add_attribute("TargetMode", "External");
+            relationship_node.add_attribute("TargetMode", "External");
         }
     }
 
diff --git a/source/s11n/style_serializer.cpp b/source/s11n/style_serializer.cpp
index f219bf39..e30cfb8f 100644
--- a/source/s11n/style_serializer.cpp
+++ b/source/s11n/style_serializer.cpp
@@ -526,28 +526,32 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
     xml.add_namespace("mc", "http://schemas.openxmlformats.org/markup-compatibility/2006");
     xml.add_namespace("x14ac", "http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac");
     
-    auto &style_sheet_node = doc.add_child("styleSheet");
-    xml.add_attribute("mc:Ignorable", "x14ac");
+    auto &style_sheet_node = xml.root();
+    style_sheet_node.set_name("styleSheet");
+    style_sheet_node.add_attribute("mc:Ignorable", "x14ac");
     
     auto num_fmts_node = style_sheet_node.add_child("numFmts");
     auto num_fmts = wb_.get_number_formats();
-    num_fmts_node.add_attribute("count", static_cast<int>(num_fmts.size()));
+    num_fmts_node.add_attribute("count", std::to_string(num_fmts.size()));
     
     for(auto &num_fmt : num_fmts)
     {
         auto num_fmt_node = num_fmts_node.add_child("numFmt");
-        num_fmt_node.add_attribute("numFmtId", num_fmt.get_id());
+        num_fmt_node.add_attribute("numFmtId", std::to_string(num_fmt.get_id()));
         num_fmt_node.add_attribute("formatCode", num_fmt.get_format_string());
     }
 
     auto fonts_node = style_sheet_node.add_child("fonts");
     auto fonts = wb_.get_fonts();
+    
     if(fonts.empty())
     {
         fonts.push_back(font());
     }
-    fonts_node.add_attribute("count", static_cast<int>(fonts.size()));
-    fonts_node.add_attribute("x14ac:knownFonts", 1);
+    
+    fonts_node.add_attribute("count", std::to_string(fonts.size()));
+    //TODO: what does this do?
+    //fonts_node.add_attribute("x14ac:knownFonts", "1");
     
     for(auto &f : fonts)
     {
@@ -556,13 +560,13 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
         if(f.is_bold())
         {
             auto bold_node = font_node.add_child("b");
-            bold_node.add_attribute("val", 1);
+            bold_node.add_attribute("val", "1");
         }
         
         if(f.is_italic())
         {
             auto bold_node = font_node.add_child("i");
-            bold_node.add_attribute("val", 1);
+            bold_node.add_attribute("val", "1");
         }
         
         if(f.is_underline())
@@ -582,21 +586,21 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
         if(f.is_strikethrough())
         {
             auto bold_node = font_node.add_child("strike");
-            bold_node.add_attribute("val", 1);
+            bold_node.add_attribute("val", "1");
         }
         
         auto size_node = font_node.add_child("sz");
-        size_node.add_attribute("val", f.get_size());
+        size_node.add_attribute("val", std::to_string(f.get_size()));
         
         auto color_node = font_node.add_child("color");
         
         if(f.get_color().get_type() == color::type::indexed)
         {
-            color_node.add_attribute("indexed", static_cast<unsigned int>(f.get_color().get_index()));
+            color_node.add_attribute("indexed", std::to_string(f.get_color().get_index()));
         }
         else if(f.get_color().get_type() == color::type::theme)
         {
-            color_node.add_attribute("theme", static_cast<unsigned int>(f.get_color().get_theme()));
+            color_node.add_attribute("theme", std::to_string(f.get_color().get_theme()));
         }
         
         auto name_node = font_node.add_child("name");
@@ -605,7 +609,7 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
         if(f.has_family())
         {
             auto family_node = font_node.add_child("family");
-            family_node.add_attribute("val", 2);
+            family_node.add_attribute("val", std::to_string(f.get_family()));
         }
         
         if(f.has_scheme())
@@ -617,7 +621,7 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
 
     auto fills_node = style_sheet_node.add_child("fills");
     const auto &fills = wb_.get_fills();
-    fills_node.add_attribute("count", static_cast<unsigned int>(fills.size()));
+    fills_node.add_attribute("count", std::to_string(fills.size()));
     
     for(auto &fill_ : fills)
     {
@@ -631,13 +635,13 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
             
             if(fill_.has_foreground_color())
             {
-                auto fg_color_node = pattern_fill_node.add_child("fgColor");
+                auto &fg_color_node = pattern_fill_node.add_child("fgColor");
                 
                 switch(fill_.get_foreground_color().get_type())
                 {
-                    case color::type::auto_: fg_color_node.add_attribute("auto", fill_.get_foreground_color().get_auto()); break;
-                    case color::type::theme: fg_color_node.add_attribute("theme", fill_.get_foreground_color().get_theme()); break;
-                    case color::type::indexed: fg_color_node.add_attribute("indexed", fill_.get_foreground_color().get_index()); break;
+                    case color::type::auto_: fg_color_node.add_attribute("auto", std::to_string(fill_.get_foreground_color().get_auto())); break;
+                    case color::type::theme: fg_color_node.add_attribute("theme", std::to_string(fill_.get_foreground_color().get_theme())); break;
+                    case color::type::indexed: fg_color_node.add_attribute("indexed", std::to_string(fill_.get_foreground_color().get_index())); break;
                     default: throw std::runtime_error("bad type");
                 }
             }
@@ -648,9 +652,9 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
                 
                 switch(fill_.get_background_color().get_type())
                 {
-                    case color::type::auto_: bg_color_node.add_attribute("auto", fill_.get_background_color().get_auto()); break;
-                    case color::type::theme: bg_color_node.add_attribute("theme", fill_.get_background_color().get_theme()); break;
-                    case color::type::indexed: bg_color_node.add_attribute("indexed", fill_.get_background_color().get_index()); break;
+                    case color::type::auto_: bg_color_node.add_attribute("auto", std::to_string(fill_.get_background_color().get_auto())); break;
+                    case color::type::theme: bg_color_node.add_attribute("theme", std::to_string(fill_.get_background_color().get_theme())); break;
+                    case color::type::indexed: bg_color_node.add_attribute("indexed", std::to_string(fill_.get_background_color().get_index())); break;
                     default: throw std::runtime_error("bad type");
                 }
             }
@@ -666,27 +670,27 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
             
             if(fill_.get_gradient_type_string() == "linear")
             {
-                gradient_fill_node.add_attribute("degree", fill_.get_rotation());
+                gradient_fill_node.add_attribute("degree", std::to_string(fill_.get_rotation()));
             }
             else if(fill_.get_gradient_type_string() == "path")
             {
-                gradient_fill_node.add_attribute("left", fill_.get_gradient_left());
-                gradient_fill_node.add_attribute("right", fill_.get_gradient_right());
-                gradient_fill_node.add_attribute("top", fill_.get_gradient_top());
-                gradient_fill_node.add_attribute("bottom", fill_.get_gradient_bottom());
+                gradient_fill_node.add_attribute("left", std::to_string(fill_.get_gradient_left()));
+                gradient_fill_node.add_attribute("right", std::to_string(fill_.get_gradient_right()));
+                gradient_fill_node.add_attribute("top", std::to_string(fill_.get_gradient_top()));
+                gradient_fill_node.add_attribute("bottom", std::to_string(fill_.get_gradient_bottom()));
                 
                 auto start_node = gradient_fill_node.add_child("stop");
-                start_node.add_attribute("position", 0);
+                start_node.add_attribute("position", "0");
                 
                 auto end_node = gradient_fill_node.add_child("stop");
-                end_node.add_attribute("position", 1);
+                end_node.add_attribute("position", "1");
             }
         }
     }
 
     auto borders_node = style_sheet_node.add_child("borders");
     const auto &borders = wb_.get_borders();
-    borders_node.add_attribute("count", static_cast<unsigned int>(borders.size()));
+    borders_node.add_attribute("count", std::to_string(borders.size()));
     
     for(const auto &border_ : borders)
     {
@@ -715,39 +719,41 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
                 
                 if(side_.is_style_assigned())
                 {
-                    auto style_attribute = side_node.add_attribute("style");
+                    std::string style_string;
                     
                     switch(side_.get_style())
                     {
-                        case border_style::none: style_attribute.set_value("none"); break;
-                        case border_style::dashdot : style_attribute.set_value("dashdot"); break;
-                        case border_style::dashdotdot : style_attribute.set_value("dashdotdot"); break;
-                        case border_style::dashed : style_attribute.set_value("dashed"); break;
-                        case border_style::dotted : style_attribute.set_value("dotted"); break;
-                        case border_style::double_ : style_attribute.set_value("double"); break;
-                        case border_style::hair : style_attribute.set_value("hair"); break;
-                        case border_style::medium : style_attribute.set_value("thin"); break;
-                        case border_style::mediumdashdot: style_attribute.set_value("mediumdashdot"); break;
-                        case border_style::mediumdashdotdot: style_attribute.set_value("mediumdashdotdot"); break;
-                        case border_style::mediumdashed: style_attribute.set_value("mediumdashed"); break;
-                        case border_style::slantdashdot: style_attribute.set_value("slantdashdot"); break;
-                        case border_style::thick: style_attribute.set_value("thick"); break;
-                        case border_style::thin: style_attribute.set_value("thin"); break;
+                        case border_style::none: style_string = "none"; break;
+                        case border_style::dashdot: style_string = "dashdot"; break;
+                        case border_style::dashdotdot: style_string = "dashdotdot"; break;
+                        case border_style::dashed: style_string = "dashed"; break;
+                        case border_style::dotted: style_string = "dotted"; break;
+                        case border_style::double_: style_string = "double"; break;
+                        case border_style::hair: style_string = "hair"; break;
+                        case border_style::medium: style_string = "thin"; break;
+                        case border_style::mediumdashdot: style_string = "mediumdashdot"; break;
+                        case border_style::mediumdashdotdot: style_string = "mediumdashdotdot"; break;
+                        case border_style::mediumdashed: style_string = "mediumdashed"; break;
+                        case border_style::slantdashdot: style_string = "slantdashdot"; break;
+                        case border_style::thick: style_string = "thick"; break;
+                        case border_style::thin: style_string = "thin"; break;
                         default: throw std::runtime_error("invalid style");
                     }
+                    
+                    side_node.add_attribute("style", style_string);
                 }
                 
                 if(side_.is_color_assigned())
                 {
                     auto color_node = side_node.add_child("color");
                     
-                    if(side_.get_color_type() == side::color_type::indexed)
+                    if(side_.get_color().get_type() == color::type::indexed)
                     {
-                        color_node.add_attribute("indexed", (int)side_.get_color());
+                        color_node.add_attribute("indexed", std::to_string(side_.get_color().get_index()));
                     }
-                    else if(side_.get_color_type() == side::color_type::theme)
+                    else if(side_.get_color().get_type() == color::type::theme)
                     {
-                        color_node.add_attribute("indexed", (int)side_.get_color());
+                        color_node.add_attribute("theme", std::to_string(side_.get_color().get_theme()));
                     }
                     else
                     {
@@ -758,40 +764,41 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
         }
     }
 
-    auto cell_style_xfs_node = style_sheet_node.add_child("cellStyleXfs");
-    cell_style_xfs_node.add_attribute("count", 1);
-    auto style_xf_node = cell_style_xfs_node.add_child("xf");
-    style_xf_node.add_attribute("numFmtId", 0);
-    style_xf_node.add_attribute("fontId", 0);
-    style_xf_node.add_attribute("fillId", 0);
-    style_xf_node.add_attribute("borderId", 0);
+    auto &cell_style_xfs_node = style_sheet_node.add_child("cellStyleXfs");
+    cell_style_xfs_node.add_attribute("count", "1");
+    
+    auto &style_xf_node = cell_style_xfs_node.add_child("xf");
+    style_xf_node.add_attribute("numFmtId", "0");
+    style_xf_node.add_attribute("fontId", "0");
+    style_xf_node.add_attribute("fillId", "0");
+    style_xf_node.add_attribute("borderId", "0");
     
     auto cell_xfs_node = style_sheet_node.add_child("cellXfs");
     const auto &styles = wb_.get_styles();
-    cell_xfs_node.add_attribute("count", static_cast<int>(styles.size()));
+    cell_xfs_node.add_attribute("count", std::to_string(styles.size()));
     
     for(auto &style : styles)
     {
         auto xf_node = cell_xfs_node.add_child("xf");
-        xf_node.add_attribute("numFmtId", style.get_number_format().get_id());
-        xf_node.add_attribute("fontId", (int)style.get_font_id());
+        xf_node.add_attribute("numFmtId", std::to_string(style.get_number_format().get_id()));
+        xf_node.add_attribute("fontId", std::to_string(style.get_font_id()));
         
         if(style.fill_apply_)
         {
-            xf_node.add_attribute("fillId", (int)style.get_fill_id());
+            xf_node.add_attribute("fillId", std::to_string(style.get_fill_id()));
         }
         
         if(style.border_apply_)
         {
-            xf_node.add_attribute("borderId", (int)style.get_border_id());
+            xf_node.add_attribute("borderId", std::to_string(style.get_border_id()));
         }
         
-        xf_node.add_attribute("applyNumberFormat", style.number_format_apply_ ? 1 : 0);
-        xf_node.add_attribute("applyFont", style.font_apply_ ? 1 : 0);
-        xf_node.add_attribute("applyFill", style.fill_apply_ ? 1 : 0);
-        xf_node.add_attribute("applyBorder", style.border_apply_ ? 1 : 0);
-        xf_node.add_attribute("applyAlignment", style.alignment_apply_ ? 1 : 0);
-        xf_node.add_attribute("applyProtection", style.protection_apply_ ? 1 : 0);
+        xf_node.add_attribute("applyNumberFormat", style.number_format_apply_ ? "1" : "0");
+        xf_node.add_attribute("applyFont", style.font_apply_ ? "1" : "0");
+        xf_node.add_attribute("applyFill", style.fill_apply_ ? "1" : "0");
+        xf_node.add_attribute("applyBorder", style.border_apply_ ? "1" : "0");
+        xf_node.add_attribute("applyAlignment", style.alignment_apply_ ? "1" : "0");
+        xf_node.add_attribute("applyProtection", style.protection_apply_ ? "1" : "0");
         
         if(style.alignment_apply_)
         {
@@ -847,22 +854,22 @@ bool style_serializer::write_stylesheet(xlnt::xml_document &xml) const
             
             if(style.alignment_.get_wrap_text())
             {
-                alignment_node.add_attribute("wrapText", 1);
+                alignment_node.add_attribute("wrapText", "1");
             }
         }
     }
 
     auto cell_styles_node = style_sheet_node.add_child("cellStyles");
-    cell_styles_node.add_attribute("count", 1);
+    cell_styles_node.add_attribute("count", "1");
     auto cell_style_node = cell_styles_node.add_child("cellStyle");
     cell_style_node.add_attribute("name", "Normal");
-    cell_style_node.add_attribute("xfId", 0);
-    cell_style_node.add_attribute("builtinId", 0);
+    cell_style_node.add_attribute("xfId", "0");
+    cell_style_node.add_attribute("builtinId", "0");
 
-    style_sheet_node.add_child("dxfs").add_attribute("count", 0);
+    style_sheet_node.add_child("dxfs").add_attribute("count", "0");
 
     auto table_styles_node = style_sheet_node.add_child("tableStyles");
-    table_styles_node.add_attribute("count", 0);
+    table_styles_node.add_attribute("count", "0");
     table_styles_node.add_attribute("defaultTableStyle", "TableStyleMedium2");
     table_styles_node.add_attribute("defaultPivotStyle", "PivotStyleMedium9");
     
diff --git a/source/s11n/theme_serializer.cpp b/source/s11n/theme_serializer.cpp
new file mode 100644
index 00000000..eff2f9e5
--- /dev/null
+++ b/source/s11n/theme_serializer.cpp
@@ -0,0 +1,356 @@
+#include <xlnt/s11n/theme_serializer.hpp>
+#include <xlnt/s11n/xml_document.hpp>
+#include <xlnt/s11n/xml_node.hpp>
+
+#include <detail/constants.hpp>
+
+namespace xlnt {
+    
+//I have no idea what this stuff is. I hope it was worth it.
+xml_document theme_serializer::write_theme(const theme &theme_)
+{
+    xml_document xml;
+    
+    xml.add_namespace("a", constants::Namespaces.at("drawingml"));
+    
+    auto &theme_node = xml.root();
+    theme_node.set_name("a:theme");
+    theme_node.add_attribute("name", "Office Theme");
+    auto &theme_elements_node = theme_node.add_child("a:themeElements");
+    auto &clr_scheme_node = theme_elements_node.add_child("a:clrScheme");
+    clr_scheme_node.add_attribute("name", "Office");
+    
+    struct scheme_element
+    {
+        std::string name;
+        std::string sub_element_name;
+        std::string val;
+    };
+    
+    std::vector<scheme_element> scheme_elements =
+    {
+        {"a:dk1", "a:sysClr", "windowText"},
+        {"a:lt1", "a:sysClr", "window"},
+        {"a:dk2", "a:srgbClr", "1F497D"},
+        {"a:lt2", "a:srgbClr", "EEECE1"},
+        {"a:accent1", "a:srgbClr", "4F81BD"},
+        {"a:accent2", "a:srgbClr", "C0504D"},
+        {"a:accent3", "a:srgbClr", "9BBB59"},
+        {"a:accent4", "a:srgbClr", "8064A2"},
+        {"a:accent5", "a:srgbClr", "4BACC6"},
+        {"a:accent6", "a:srgbClr", "F79646"},
+        {"a:hlink", "a:srgbClr", "0000FF"},
+        {"a:folHlink", "a:srgbClr", "800080"},
+    };
+    
+    for(auto element : scheme_elements)
+    {
+        auto element_node = clr_scheme_node.add_child(element.name);
+        element_node.add_child(element.sub_element_name).add_attribute("val", element.val);
+        
+        if(element.name == "a:dk1")
+        {
+            element_node.get_child(element.sub_element_name).add_attribute("lastClr", "000000");
+        }
+        else if(element.name == "a:lt1")
+        {
+            element_node.get_child(element.sub_element_name).add_attribute("lastClr", "FFFFFF");
+        }
+    }
+    
+    struct font_scheme
+    {
+        bool typeface;
+        std::string script;
+        std::string major;
+        std::string minor;
+    };
+    
+    std::vector<font_scheme> font_schemes =
+    {
+        {true, "a:latin", "Cambria", "Calibri"},
+        {true, "a:ea", "", ""},
+        {true, "a:cs", "", ""},
+        {false, "Jpan", "\xef\xbc\xad\xef\xbc\xb3 \xef\xbc\xb0\xe3\x82\xb4\xe3\x82\xb7\xe3\x83\x83\xe3\x82\xaf", "\xef\xbc\xad\xef\xbc\xb3 \xef\xbc\xb0\xe3\x82\xb4\xe3\x82\xb7\xe3\x83\x83\xe3\x82\xaf"},
+        {false, "Hang", "\xeb\xa7\x91\xec\x9d\x80 \xea\xb3\xa0\xeb\x94\x95", "\xeb\xa7\x91\xec\x9d\x80 \xea\xb3\xa0\xeb\x94\x95"},
+        {false, "Hans", "\xe5\xae\x8b\xe4\xbd\x93", "\xe5\xae\x8b\xe4\xbd\x93"},
+        {false, "Hant", "\xe6\x96\xb0\xe7\xb4\xb0\xe6\x98\x8e\xe9\xab\x94", "\xe6\x96\xb0\xe7\xb4\xb0\xe6\x98\x8e\xe9\xab\x94"},
+        {false, "Arab", "Times New Roman", "Arial"},
+        {false, "Hebr", "Times New Roman", "Arial"},
+        {false, "Thai", "Tahoma", "Tahoma"},
+        {false, "Ethi", "Nyala", "Nyala"},
+        {false, "Beng", "Vrinda", "Vrinda"},
+        {false, "Gujr", "Shruti", "Shruti"},
+        {false, "Khmr", "MoolBoran", "DaunPenh"},
+        {false, "Knda", "Tunga", "Tunga"},
+        {false, "Guru", "Raavi", "Raavi"},
+        {false, "Cans", "Euphemia", "Euphemia"},
+        {false, "Cher", "Plantagenet Cherokee", "Plantagenet Cherokee"},
+        {false, "Yiii", "Microsoft Yi Baiti", "Microsoft Yi Baiti"},
+        {false, "Tibt", "Microsoft Himalaya", "Microsoft Himalaya"},
+        {false, "Thaa", "MV Boli", "MV Boli"},
+        {false, "Deva", "Mangal", "Mangal"},
+        {false, "Telu", "Gautami", "Gautami"},
+        {false, "Taml", "Latha", "Latha"},
+        {false, "Syrc", "Estrangelo Edessa", "Estrangelo Edessa"},
+        {false, "Orya", "Kalinga", "Kalinga"},
+        {false, "Mlym", "Kartika", "Kartika"},
+        {false, "Laoo", "DokChampa", "DokChampa"},
+        {false, "Sinh", "Iskoola Pota", "Iskoola Pota"},
+        {false, "Mong", "Mongolian Baiti", "Mongolian Baiti"},
+        {false, "Viet", "Times New Roman", "Arial"},
+        {false, "Uigh", "Microsoft Uighur", "Microsoft Uighur"}
+    };
+    
+    auto font_scheme_node = theme_elements_node.add_child("a:fontScheme");
+    font_scheme_node.add_attribute("name", "Office");
+    
+    auto major_fonts_node = font_scheme_node.add_child("a:majorFont");
+    auto minor_fonts_node = font_scheme_node.add_child("a:minorFont");
+    
+    for(auto scheme : font_schemes)
+    {
+        if(scheme.typeface)
+        {
+            auto &major_font_node = major_fonts_node.add_child(scheme.script);
+            major_font_node.add_attribute("typeface", scheme.major);
+            
+            auto &minor_font_node = minor_fonts_node.add_child(scheme.script);
+            minor_font_node.add_attribute("typeface", scheme.minor);
+        }
+        else
+        {
+            auto &major_font_node = major_fonts_node.add_child("a:font");
+            major_font_node.add_attribute("script", scheme.script);
+            major_font_node.add_attribute("typeface", scheme.major);
+            
+            auto &minor_font_node = minor_fonts_node.add_child("a:font");
+            minor_font_node.add_attribute("script", scheme.script);
+            minor_font_node.add_attribute("typeface", scheme.minor);
+        }
+    }
+    
+    auto format_scheme_node = theme_elements_node.add_child("a:fmtScheme");
+    format_scheme_node.add_attribute("name", "Office");
+    
+    auto fill_style_list_node = format_scheme_node.add_child("a:fillStyleLst");
+    fill_style_list_node.add_child("a:solidFill").add_child("a:schemeClr").add_attribute("val", "phClr");
+    
+    auto grad_fill_node = fill_style_list_node.add_child("a:gradFill");
+    grad_fill_node.add_attribute("rotWithShape", "1");
+    
+    auto grad_fill_list = grad_fill_node.add_child("a:gsLst");
+    auto gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", 0);
+    auto scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:tint").add_attribute("val", "50000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "300000");
+    
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "35000");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:tint").add_attribute("val", "37000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "300000");
+    
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "100000");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:tint").add_attribute("val", "15000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "350000");
+    
+    auto lin_node = grad_fill_node.add_child("a:lin");
+    lin_node.add_attribute("ang", "16200000");
+    lin_node.add_attribute("scaled", "1");
+    
+    grad_fill_node = fill_style_list_node.add_child("a:gradFill");
+    grad_fill_node.add_attribute("rotWithShape", "1");
+    
+    grad_fill_list = grad_fill_node.add_child("a:gsLst");
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "0");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:shade").add_attribute("val", "51000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "130000");
+    
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "80000");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:shade").add_attribute("val", "93000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "130000");
+    
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "100000");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:shade").add_attribute("val", "94000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "135000");
+    
+    lin_node = grad_fill_node.add_child("a:lin");
+    lin_node.add_attribute("ang", "16200000");
+    lin_node.add_attribute("scaled", "0");
+    
+    auto line_style_list_node = format_scheme_node.add_child("a:lnStyleLst");
+    
+    auto ln_node = line_style_list_node.add_child("a:ln");
+    ln_node.add_attribute("w", "9525");
+    ln_node.add_attribute("cap", "flat");
+    ln_node.add_attribute("cmpd", "sng");
+    ln_node.add_attribute("algn", "ctr");
+    
+    auto solid_fill_node = ln_node.add_child("a:solidFill");
+    scheme_color_node = solid_fill_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:shade").add_attribute("val", "95000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "105000");
+    ln_node.add_child("a:prstDash").add_attribute("val", "solid");
+    
+    ln_node = line_style_list_node.add_child("a:ln");
+    ln_node.add_attribute("w", "25400");
+    ln_node.add_attribute("cap", "flat");
+    ln_node.add_attribute("cmpd", "sng");
+    ln_node.add_attribute("algn", "ctr");
+    
+    solid_fill_node = ln_node.add_child("a:solidFill");
+    scheme_color_node = solid_fill_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    ln_node.add_child("a:prstDash").add_attribute("val", "solid");
+    
+    ln_node = line_style_list_node.add_child("a:ln");
+    ln_node.add_attribute("w", "38100");
+    ln_node.add_attribute("cap", "flat");
+    ln_node.add_attribute("cmpd", "sng");
+    ln_node.add_attribute("algn", "ctr");
+    
+    solid_fill_node = ln_node.add_child("a:solidFill");
+    scheme_color_node = solid_fill_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    ln_node.add_child("a:prstDash").add_attribute("val", "solid");
+    
+    auto effect_style_list_node = format_scheme_node.add_child("a:effectStyleLst");
+    auto effect_style_node = effect_style_list_node.add_child("a:effectStyle");
+    auto effect_list_node = effect_style_node.add_child("a:effectLst");
+    auto outer_shadow_node = effect_list_node.add_child("a:outerShdw");
+    outer_shadow_node.add_attribute("blurRad", "40000");
+    outer_shadow_node.add_attribute("dist", "20000");
+    outer_shadow_node.add_attribute("dir", "5400000");
+    outer_shadow_node.add_attribute("rotWithShape", "0");
+    auto srgb_clr_node = outer_shadow_node.add_child("a:srgbClr");
+    srgb_clr_node.add_attribute("val", "000000");
+    srgb_clr_node.add_child("a:alpha").add_attribute("val", "38000");
+    
+    effect_style_node = effect_style_list_node.add_child("a:effectStyle");
+    effect_list_node = effect_style_node.add_child("a:effectLst");
+    outer_shadow_node = effect_list_node.add_child("a:outerShdw");
+    outer_shadow_node.add_attribute("blurRad", "40000");
+    outer_shadow_node.add_attribute("dist", "23000");
+    outer_shadow_node.add_attribute("dir", "5400000");
+    outer_shadow_node.add_attribute("rotWithShape", "0");
+    srgb_clr_node = outer_shadow_node.add_child("a:srgbClr");
+    srgb_clr_node.add_attribute("val", "000000");
+    srgb_clr_node.add_child("a:alpha").add_attribute("val", "35000");
+    
+    effect_style_node = effect_style_list_node.add_child("a:effectStyle");
+    effect_list_node = effect_style_node.add_child("a:effectLst");
+    outer_shadow_node = effect_list_node.add_child("a:outerShdw");
+    outer_shadow_node.add_attribute("blurRad", "40000");
+    outer_shadow_node.add_attribute("dist", "23000");
+    outer_shadow_node.add_attribute("dir", "5400000");
+    outer_shadow_node.add_attribute("rotWithShape", "0");
+    srgb_clr_node = outer_shadow_node.add_child("a:srgbClr");
+    srgb_clr_node.add_attribute("val", "000000");
+    srgb_clr_node.add_child("a:alpha").add_attribute("val", "35000");
+    auto scene3d_node = effect_style_node.add_child("a:scene3d");
+    auto camera_node = scene3d_node.add_child("a:camera");
+    camera_node.add_attribute("prst", "orthographicFront");
+    auto rot_node = camera_node.add_child("a:rot");
+    rot_node.add_attribute("lat", "0");
+    rot_node.add_attribute("lon", "0");
+    rot_node.add_attribute("rev", "0");
+    auto light_rig_node = scene3d_node.add_child("a:lightRig");
+    light_rig_node.add_attribute("rig", "threePt");
+    light_rig_node.add_attribute("dir", "t");
+    rot_node = light_rig_node.add_child("a:rot");
+    rot_node.add_attribute("lat", "0");
+    rot_node.add_attribute("lon", "0");
+    rot_node.add_attribute("rev", "1200000");
+    
+    auto bevel_node = effect_style_node.add_child("a:sp3d").add_child("a:bevelT");
+    bevel_node.add_attribute("w", "63500");
+    bevel_node.add_attribute("h", "25400");
+    
+    auto bg_fill_style_list_node = format_scheme_node.add_child("a:bgFillStyleLst");
+    
+    bg_fill_style_list_node.add_child("a:solidFill").add_child("a:schemeClr").add_attribute("val", "phClr");
+    
+    grad_fill_node = bg_fill_style_list_node.add_child("a:gradFill");
+    grad_fill_node.add_attribute("rotWithShape", "1");
+    
+    grad_fill_list = grad_fill_node.add_child("a:gsLst");
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "0");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:tint").add_attribute("val", "40000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "350000");
+    
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "40000");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:tint").add_attribute("val", "45000");
+    scheme_color_node.add_child("a:shade").add_attribute("val", "99000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "350000");
+    
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "100000");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:shade").add_attribute("val", "20000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "255000");
+    
+    auto path_node = grad_fill_node.add_child("a:path");
+    path_node.add_attribute("path", "circle");
+    auto fill_to_rect_node = path_node.add_child("a:fillToRect");
+    fill_to_rect_node.add_attribute("l", "50000");
+    fill_to_rect_node.add_attribute("t", "-80000");
+    fill_to_rect_node.add_attribute("r", "50000");
+    fill_to_rect_node.add_attribute("b", "180000");
+    
+    grad_fill_node = bg_fill_style_list_node.add_child("a:gradFill");
+    grad_fill_node.add_attribute("rotWithShape", "1");
+    
+    grad_fill_list = grad_fill_node.add_child("a:gsLst");
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "0");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:tint").add_attribute("val", "80000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "300000");
+    
+    gs_node = grad_fill_list.add_child("a:gs");
+    gs_node.add_attribute("pos", "100000");
+    scheme_color_node = gs_node.add_child("a:schemeClr");
+    scheme_color_node.add_attribute("val", "phClr");
+    scheme_color_node.add_child("a:shade").add_attribute("val", "30000");
+    scheme_color_node.add_child("a:satMod").add_attribute("val", "200000");
+    
+    path_node = grad_fill_node.add_child("a:path");
+    path_node.add_attribute("path", "circle");
+    fill_to_rect_node = path_node.add_child("a:fillToRect");
+    fill_to_rect_node.add_attribute("l", "50000");
+    fill_to_rect_node.add_attribute("t", "50000");
+    fill_to_rect_node.add_attribute("r", "50000");
+    fill_to_rect_node.add_attribute("b", "50000");
+    
+    theme_node.add_child("a:objectDefaults");
+    theme_node.add_child("a:extraClrSchemeLst");
+    
+    return xml;
+}
+    
+} // namespace xlnt
diff --git a/source/s11n/workbook_serializer.cpp b/source/s11n/workbook_serializer.cpp
index ed8834d2..e7ca1cfc 100644
--- a/source/s11n/workbook_serializer.cpp
+++ b/source/s11n/workbook_serializer.cpp
@@ -1,11 +1,15 @@
 #include <xlnt/s11n/workbook_serializer.hpp>
 #include <xlnt/common/datetime.hpp>
+#include <xlnt/common/exceptions.hpp>
 #include <xlnt/common/relationship.hpp>
 #include <xlnt/s11n/xml_document.hpp>
 #include <xlnt/s11n/xml_node.hpp>
 #include <xlnt/workbook/document_properties.hpp>
 #include <xlnt/workbook/manifest.hpp>
+#include <xlnt/workbook/named_range.hpp>
 #include <xlnt/workbook/workbook.hpp>
+#include <xlnt/worksheet/range_reference.hpp>
+#include <xlnt/worksheet/worksheet.hpp>
 
 #include "detail/constants.hpp"
 
@@ -66,15 +70,15 @@ std::vector<std::pair<std::string, std::string>> workbook_serializer::read_sheet
     
     auto with_ns = [&](const std::string &base) { return ns.empty() ? base : ns + ":" + base; };
     
-    auto root_node = doc.child(with_ns("workbook").c_str());
-    auto sheets_node = root_node.child(with_ns("sheets").c_str());
+    auto root_node = doc.get_child(with_ns("workbook"));
+    auto sheets_node = root_node.get_child(with_ns("sheets"));
     
     std::vector<std::pair<std::string, std::string>> sheets;
     
     // store temp because pugixml iteration uses the internal char array multiple times
     auto sheet_element_name = with_ns("sheet");
     
-    for(auto sheet_node : sheets_node.children(sheet_element_name.c_str()))
+    for(auto sheet_node : sheets_node.children(sheet_element_name))
     {
         std::string id = sheet_node.attribute("r:id").as_string();
         std::string name = sheet_node.attribute("name").as_string();
@@ -112,53 +116,6 @@ void workbook_serializer::read_properties_core(const xml_document &xml)
     }
 }
 
-std::string workbook_serializer::read_dimension(const std::string &xml_string)
-{
-    pugi::xml_document doc;
-    doc.load(xml_string.c_str());
-    auto root_node = doc.child("worksheet");
-    auto dimension_node = root_node.child("dimension");
-    std::string dimension = dimension_node.attribute("ref").as_string();
-    return dimension;
-}
-
-std::vector<relationship> workbook_serializer::read_relationships(zip_file &archive, const std::string &filename)
-{
-    auto filename_separator_index = filename.find_last_of('/');
-    auto basename = filename.substr(filename_separator_index + 1);
-    auto dirname = filename.substr(0, filename_separator_index);
-    auto rels_filename = dirname + "/_rels/" + basename + ".rels";
-    
-    pugi::xml_document doc;
-    auto content = archive.read(rels_filename);
-    doc.load(content.c_str());
-    
-    auto root_node = doc.child("Relationships");
-    
-    std::vector<relationship> relationships;
-    
-    for(auto relationship : root_node.children("Relationship"))
-    {
-        std::string id = relationship.attribute("Id").as_string();
-        std::string type = relationship.attribute("Type").as_string();
-        std::string target = relationship.attribute("Target").as_string();
-        
-        if(target[0] != '/' && target.substr(0, 2) != "..")
-        {
-            target = dirname + "/" + target;
-        }
-        
-        if(target[0] == '/')
-        {
-            target = target.substr(1);
-        }
-        
-        relationships.push_back(xlnt::relationship(type, id, target));
-    }
-    
-    return relationships;
-}
-
 std::string workbook_serializer::determine_document_type(const manifest &manifest)
 {
     if(!manifest.has_override_type(constants::ArcWorkbook))
@@ -184,22 +141,27 @@ std::string workbook_serializer::determine_document_type(const manifest &manifes
     return "unsupported";
 }
 
+/// <summary>
+/// Return a list of worksheets.
+/// content types has a list of paths but no titles
+/// workbook has a list of titles and relIds but no paths
+/// workbook_rels has a list of relIds and paths but no titles
+/// </summary>
 std::vector<std::pair<std::string, std::string>> workbook_serializer::detect_worksheets(zip_file &archive)
 {
     static const std::string ValidWorksheet = "application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml";
     
-    auto content_types = read_content_types(archive);
     std::vector<std::string> valid_sheets;
     
-    for(const auto &content_type : content_types)
+    for(const auto &content_type : wb_.get_manifest().get_override_types())
     {
-        if(content_type.second == ValidWorksheet)
+        if(content_type.get_content_type() == ValidWorksheet)
         {
-            valid_sheets.push_back(content_type.first);
+            valid_sheets.push_back(content_type.get_part_name());
         }
     }
     
-    auto workbook_relationships = read_relationships(archive, "xl/workbook.xml");
+    auto &workbook_relationships = wb_.get_relationships();
     std::vector<std::pair<std::string, std::string>> result;
     
     for(const auto &ws : read_sheets(archive))
@@ -216,456 +178,80 @@ std::vector<std::pair<std::string, std::string>> workbook_serializer::detect_wor
     return result;
 }
 
-std::string workbook_serializer::write_shared_strings(const std::vector<std::string> &string_table)
+xml_document workbook_serializer::write_properties_core() const
 {
-    pugi::xml_document doc;
-    auto root_node = doc.append_child("sst");
-    root_node.append_attribute("xmlns").set_value("http://schemas.openxmlformats.org/spreadsheetml/2006/main");
-    root_node.append_attribute("uniqueCount").set_value((int)string_table.size());
+    auto &props = wb_.get_properties();
     
-    for(auto string : string_table)
+    xml_document xml;
+    
+    xml.add_namespace("cp", "http://schemas.openxmlformats.org/package/2006/metadata/core-properties");
+    xml.add_namespace("dc", "http://purl.org/dc/elements/1.1/");
+    xml.add_namespace("dcmitype", "http://purl.org/dc/dcmitype/");
+    xml.add_namespace("dcterms", "http://purl.org/dc/terms/");
+    xml.add_namespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
+    
+    auto &root_node = xml.root();
+    root_node.set_name("cp:coreProperties");
+    
+    root_node.add_child("dc:creator").set_text(props.creator);
+    root_node.add_child("cp:lastModifiedBy").set_text(props.last_modified_by);
+    root_node.add_child("dcterms:created").set_text(datetime_to_w3cdtf(props.created));
+    root_node.get_child("dcterms:created").add_attribute("xsi:type", "dcterms:W3CDTF");
+    root_node.add_child("dcterms:modified").set_text(datetime_to_w3cdtf(props.modified));
+    root_node.get_child("dcterms:modified").add_attribute("xsi:type", "dcterms:W3CDTF");
+    root_node.add_child("dc:title").set_text(props.title);
+    root_node.add_child("dc:description");
+    root_node.add_child("dc:subject");
+    root_node.add_child("cp:keywords");
+    root_node.add_child("cp:category");
+    
+    return xml;
+}
+    
+xml_document workbook_serializer::write_properties_app() const
+{
+    xml_document xml;
+    
+    xml.add_namespace("xmlns", "http://schemas.openxmlformats.org/officeDocument/2006/extended-properties");
+    xml.add_namespace("xmlns:vt", "http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes");
+    
+    auto &root_node = xml.root();
+    root_node.set_name("Properties");
+    
+    root_node.add_child("Application").set_text("Microsoft Excel");
+    root_node.add_child("DocSecurity").set_text("0");
+    root_node.add_child("ScaleCrop").set_text("false");
+    root_node.add_child("Company");
+    root_node.add_child("LinksUpToDate").set_text("false");
+    root_node.add_child("SharedDoc").set_text("false");
+    root_node.add_child("HyperlinksChanged").set_text("false");
+    root_node.add_child("AppVersion").set_text("12.0000");
+    
+    auto heading_pairs_node = root_node.add_child("HeadingPairs");
+    auto heading_pairs_vector_node = heading_pairs_node.add_child("vt:vector");
+    heading_pairs_vector_node.add_attribute("baseType", "variant");
+    heading_pairs_vector_node.add_attribute("size", "2");
+    heading_pairs_vector_node.add_child("vt:variant").add_child("vt:lpstr").set_text("Worksheets");
+    heading_pairs_vector_node.add_child("vt:variant").add_child("vt:i4").set_text(std::to_string(wb_.get_sheet_names().size()));
+    
+    auto titles_of_parts_node = root_node.add_child("TitlesOfParts");
+    auto titles_of_parts_vector_node = titles_of_parts_node.add_child("vt:vector");
+    titles_of_parts_vector_node.add_attribute("baseType", "lpstr");
+    titles_of_parts_vector_node.add_attribute("size", std::to_string(wb_.get_sheet_names().size()));
+    
+    for(auto ws : wb_)
     {
-        root_node.append_child("si").append_child("t").text().set(string.c_str());
+        titles_of_parts_vector_node.add_child("vt:lpstr").set_text(ws.get_title());
     }
-    
-    std::stringstream ss;
-    doc.save(ss);
-    
-    return ss.str();
+
+    return xml;
 }
 
-std::string workbook_serializer::write_properties_core(const document_properties &prop)
-{
-    pugi::xml_document doc;
-    auto root_node = doc.append_child("cp:coreProperties");
-    root_node.append_attribute("xmlns:cp").set_value("http://schemas.openxmlformats.org/package/2006/metadata/core-properties");
-    root_node.append_attribute("xmlns:dc").set_value("http://purl.org/dc/elements/1.1/");
-    root_node.append_attribute("xmlns:dcmitype").set_value("http://purl.org/dc/dcmitype/");
-    root_node.append_attribute("xmlns:dcterms").set_value("http://purl.org/dc/terms/");
-    root_node.append_attribute("xmlns:xsi").set_value("http://www.w3.org/2001/XMLSchema-instance");
-    
-    root_node.append_child("dc:creator").text().set(prop.creator.c_str());
-    root_node.append_child("cp:lastModifiedBy").text().set(prop.last_modified_by.c_str());
-    root_node.append_child("dcterms:created").text().set(datetime_to_w3cdtf(prop.created).c_str());
-    root_node.child("dcterms:created").append_attribute("xsi:type").set_value("dcterms:W3CDTF");
-    root_node.append_child("dcterms:modified").text().set(datetime_to_w3cdtf(prop.modified).c_str());
-    root_node.child("dcterms:modified").append_attribute("xsi:type").set_value("dcterms:W3CDTF");
-    root_node.append_child("dc:title").text().set(prop.title.c_str());
-    root_node.append_child("dc:description");
-    root_node.append_child("dc:subject");
-    root_node.append_child("cp:keywords");
-    root_node.append_child("cp:category");
-    
-    std::stringstream ss;
-    doc.save(ss);
-    
-    return ss.str();
-}
-
-std::string workbook_serializer::write_worksheet_rels(worksheet ws)
-{
-    return write_relationships(ws.get_relationships(), "");
-}
-
-std::string workbook_serializer::write_theme()
-{
-    pugi::xml_document doc;
-    auto theme_node = doc.append_child("a:theme");
-    theme_node.append_attribute("xmlns:a").set_value(constants::Namespaces.at("drawingml").c_str());
-    theme_node.append_attribute("name").set_value("Office Theme");
-    auto theme_elements_node = theme_node.append_child("a:themeElements");
-    auto clr_scheme_node = theme_elements_node.append_child("a:clrScheme");
-    clr_scheme_node.append_attribute("name").set_value("Office");
-    
-    struct scheme_element
-    {
-        std::string name;
-        std::string sub_element_name;
-        std::string val;
-    };
-    
-    std::vector<scheme_element> scheme_elements =
-    {
-        {"a:dk1", "a:sysClr", "windowText"},
-        {"a:lt1", "a:sysClr", "window"},
-        {"a:dk2", "a:srgbClr", "1F497D"},
-        {"a:lt2", "a:srgbClr", "EEECE1"},
-        {"a:accent1", "a:srgbClr", "4F81BD"},
-        {"a:accent2", "a:srgbClr", "C0504D"},
-        {"a:accent3", "a:srgbClr", "9BBB59"},
-        {"a:accent4", "a:srgbClr", "8064A2"},
-        {"a:accent5", "a:srgbClr", "4BACC6"},
-        {"a:accent6", "a:srgbClr", "F79646"},
-        {"a:hlink", "a:srgbClr", "0000FF"},
-        {"a:folHlink", "a:srgbClr", "800080"},
-    };
-    
-    for(auto element : scheme_elements)
-    {
-        auto element_node = clr_scheme_node.append_child(element.name.c_str());
-        element_node.append_child(element.sub_element_name.c_str()).append_attribute("val").set_value(element.val.c_str());
-        
-        if(element.name == "a:dk1")
-        {
-            element_node.child(element.sub_element_name.c_str()).append_attribute("lastClr").set_value("000000");
-        }
-        else if(element.name == "a:lt1")
-        {
-            element_node.child(element.sub_element_name.c_str()).append_attribute("lastClr").set_value("FFFFFF");
-        }
-    }
-    
-    struct font_scheme
-    {
-        bool typeface;
-        std::string script;
-        std::string major;
-        std::string minor;
-    };
-    
-    std::vector<font_scheme> font_schemes =
-    {
-        {true, "a:latin", "Cambria", "Calibri"},
-        {true, "a:ea", "", ""},
-        {true, "a:cs", "", ""},
-        {false, "Jpan", "\xef\xbc\xad\xef\xbc\xb3 \xef\xbc\xb0\xe3\x82\xb4\xe3\x82\xb7\xe3\x83\x83\xe3\x82\xaf", "\xef\xbc\xad\xef\xbc\xb3 \xef\xbc\xb0\xe3\x82\xb4\xe3\x82\xb7\xe3\x83\x83\xe3\x82\xaf"},
-        {false, "Hang", "\xeb\xa7\x91\xec\x9d\x80 \xea\xb3\xa0\xeb\x94\x95", "\xeb\xa7\x91\xec\x9d\x80 \xea\xb3\xa0\xeb\x94\x95"},
-        {false, "Hans", "\xe5\xae\x8b\xe4\xbd\x93", "\xe5\xae\x8b\xe4\xbd\x93"},
-        {false, "Hant", "\xe6\x96\xb0\xe7\xb4\xb0\xe6\x98\x8e\xe9\xab\x94", "\xe6\x96\xb0\xe7\xb4\xb0\xe6\x98\x8e\xe9\xab\x94"},
-        {false, "Arab", "Times New Roman", "Arial"},
-        {false, "Hebr", "Times New Roman", "Arial"},
-        {false, "Thai", "Tahoma", "Tahoma"},
-        {false, "Ethi", "Nyala", "Nyala"},
-        {false, "Beng", "Vrinda", "Vrinda"},
-        {false, "Gujr", "Shruti", "Shruti"},
-        {false, "Khmr", "MoolBoran", "DaunPenh"},
-        {false, "Knda", "Tunga", "Tunga"},
-        {false, "Guru", "Raavi", "Raavi"},
-        {false, "Cans", "Euphemia", "Euphemia"},
-        {false, "Cher", "Plantagenet Cherokee", "Plantagenet Cherokee"},
-        {false, "Yiii", "Microsoft Yi Baiti", "Microsoft Yi Baiti"},
-        {false, "Tibt", "Microsoft Himalaya", "Microsoft Himalaya"},
-        {false, "Thaa", "MV Boli", "MV Boli"},
-        {false, "Deva", "Mangal", "Mangal"},
-        {false, "Telu", "Gautami", "Gautami"},
-        {false, "Taml", "Latha", "Latha"},
-        {false, "Syrc", "Estrangelo Edessa", "Estrangelo Edessa"},
-        {false, "Orya", "Kalinga", "Kalinga"},
-        {false, "Mlym", "Kartika", "Kartika"},
-        {false, "Laoo", "DokChampa", "DokChampa"},
-        {false, "Sinh", "Iskoola Pota", "Iskoola Pota"},
-        {false, "Mong", "Mongolian Baiti", "Mongolian Baiti"},
-        {false, "Viet", "Times New Roman", "Arial"},
-        {false, "Uigh", "Microsoft Uighur", "Microsoft Uighur"}
-    };
-    
-    auto font_scheme_node = theme_elements_node.append_child("a:fontScheme");
-    font_scheme_node.append_attribute("name").set_value("Office");
-    
-    auto major_fonts_node = font_scheme_node.append_child("a:majorFont");
-    auto minor_fonts_node = font_scheme_node.append_child("a:minorFont");
-    
-    for(auto scheme : font_schemes)
-    {
-        pugi::xml_node major_font_node, minor_font_node;
-        
-        if(scheme.typeface)
-        {
-            major_font_node = major_fonts_node.append_child(scheme.script.c_str());
-            minor_font_node = minor_fonts_node.append_child(scheme.script.c_str());
-        }
-        else
-        {
-            major_font_node = major_fonts_node.append_child("a:font");
-            major_font_node.append_attribute("script").set_value(scheme.script.c_str());
-            minor_font_node = minor_fonts_node.append_child("a:font");
-            minor_font_node.append_attribute("script").set_value(scheme.script.c_str());
-        }
-        
-        major_font_node.append_attribute("typeface").set_value(scheme.major.c_str());
-        minor_font_node.append_attribute("typeface").set_value(scheme.minor.c_str());
-    }
-    
-    auto format_scheme_node = theme_elements_node.append_child("a:fmtScheme");
-    format_scheme_node.append_attribute("name").set_value("Office");
-    
-    auto fill_style_list_node = format_scheme_node.append_child("a:fillStyleLst");
-    fill_style_list_node.append_child("a:solidFill").append_child("a:schemeClr").append_attribute("val").set_value("phClr");
-    
-    auto grad_fill_node = fill_style_list_node.append_child("a:gradFill");
-    grad_fill_node.append_attribute("rotWithShape").set_value(1);
-    
-    auto grad_fill_list = grad_fill_node.append_child("a:gsLst");
-    auto gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(0);
-    auto scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:tint").append_attribute("val").set_value(50000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(300000);
-    
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(35000);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:tint").append_attribute("val").set_value(37000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(300000);
-    
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(100000);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:tint").append_attribute("val").set_value(15000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(350000);
-    
-    auto lin_node = grad_fill_node.append_child("a:lin");
-    lin_node.append_attribute("ang").set_value(16200000);
-    lin_node.append_attribute("scaled").set_value(1);
-    
-    grad_fill_node = fill_style_list_node.append_child("a:gradFill");
-    grad_fill_node.append_attribute("rotWithShape").set_value(1);
-    
-    grad_fill_list = grad_fill_node.append_child("a:gsLst");
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(0);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:shade").append_attribute("val").set_value(51000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(130000);
-    
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(80000);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:shade").append_attribute("val").set_value(93000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(130000);
-    
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(100000);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:shade").append_attribute("val").set_value(94000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(135000);
-    
-    lin_node = grad_fill_node.append_child("a:lin");
-    lin_node.append_attribute("ang").set_value(16200000);
-    lin_node.append_attribute("scaled").set_value(0);
-    
-    auto line_style_list_node = format_scheme_node.append_child("a:lnStyleLst");
-    
-    auto ln_node = line_style_list_node.append_child("a:ln");
-    ln_node.append_attribute("w").set_value(9525);
-    ln_node.append_attribute("cap").set_value("flat");
-    ln_node.append_attribute("cmpd").set_value("sng");
-    ln_node.append_attribute("algn").set_value("ctr");
-    
-    auto solid_fill_node = ln_node.append_child("a:solidFill");
-    scheme_color_node = solid_fill_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:shade").append_attribute("val").set_value(95000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(105000);
-    ln_node.append_child("a:prstDash").append_attribute("val").set_value("solid");
-    
-    ln_node = line_style_list_node.append_child("a:ln");
-    ln_node.append_attribute("w").set_value(25400);
-    ln_node.append_attribute("cap").set_value("flat");
-    ln_node.append_attribute("cmpd").set_value("sng");
-    ln_node.append_attribute("algn").set_value("ctr");
-    
-    solid_fill_node = ln_node.append_child("a:solidFill");
-    scheme_color_node = solid_fill_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    ln_node.append_child("a:prstDash").append_attribute("val").set_value("solid");
-    
-    ln_node = line_style_list_node.append_child("a:ln");
-    ln_node.append_attribute("w").set_value(38100);
-    ln_node.append_attribute("cap").set_value("flat");
-    ln_node.append_attribute("cmpd").set_value("sng");
-    ln_node.append_attribute("algn").set_value("ctr");
-    
-    solid_fill_node = ln_node.append_child("a:solidFill");
-    scheme_color_node = solid_fill_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    ln_node.append_child("a:prstDash").append_attribute("val").set_value("solid");
-    
-    auto effect_style_list_node = format_scheme_node.append_child("a:effectStyleLst");
-    auto effect_style_node = effect_style_list_node.append_child("a:effectStyle");
-    auto effect_list_node = effect_style_node.append_child("a:effectLst");
-    auto outer_shadow_node = effect_list_node.append_child("a:outerShdw");
-    outer_shadow_node.append_attribute("blurRad").set_value(40000);
-    outer_shadow_node.append_attribute("dist").set_value(20000);
-    outer_shadow_node.append_attribute("dir").set_value(5400000);
-    outer_shadow_node.append_attribute("rotWithShape").set_value(0);
-    auto srgb_clr_node = outer_shadow_node.append_child("a:srgbClr");
-    srgb_clr_node.append_attribute("val").set_value("000000");
-    srgb_clr_node.append_child("a:alpha").append_attribute("val").set_value(38000);
-    
-    effect_style_node = effect_style_list_node.append_child("a:effectStyle");
-    effect_list_node = effect_style_node.append_child("a:effectLst");
-    outer_shadow_node = effect_list_node.append_child("a:outerShdw");
-    outer_shadow_node.append_attribute("blurRad").set_value(40000);
-    outer_shadow_node.append_attribute("dist").set_value(23000);
-    outer_shadow_node.append_attribute("dir").set_value(5400000);
-    outer_shadow_node.append_attribute("rotWithShape").set_value(0);
-    srgb_clr_node = outer_shadow_node.append_child("a:srgbClr");
-    srgb_clr_node.append_attribute("val").set_value("000000");
-    srgb_clr_node.append_child("a:alpha").append_attribute("val").set_value(35000);
-    
-    effect_style_node = effect_style_list_node.append_child("a:effectStyle");
-    effect_list_node = effect_style_node.append_child("a:effectLst");
-    outer_shadow_node = effect_list_node.append_child("a:outerShdw");
-    outer_shadow_node.append_attribute("blurRad").set_value(40000);
-    outer_shadow_node.append_attribute("dist").set_value(23000);
-    outer_shadow_node.append_attribute("dir").set_value(5400000);
-    outer_shadow_node.append_attribute("rotWithShape").set_value(0);
-    srgb_clr_node = outer_shadow_node.append_child("a:srgbClr");
-    srgb_clr_node.append_attribute("val").set_value("000000");
-    srgb_clr_node.append_child("a:alpha").append_attribute("val").set_value(35000);
-    auto scene3d_node = effect_style_node.append_child("a:scene3d");
-    auto camera_node = scene3d_node.append_child("a:camera");
-    camera_node.append_attribute("prst").set_value("orthographicFront");
-    auto rot_node = camera_node.append_child("a:rot");
-    rot_node.append_attribute("lat").set_value(0);
-    rot_node.append_attribute("lon").set_value(0);
-    rot_node.append_attribute("rev").set_value(0);
-    auto light_rig_node = scene3d_node.append_child("a:lightRig");
-    light_rig_node.append_attribute("rig").set_value("threePt");
-    light_rig_node.append_attribute("dir").set_value("t");
-    rot_node = light_rig_node.append_child("a:rot");
-    rot_node.append_attribute("lat").set_value(0);
-    rot_node.append_attribute("lon").set_value(0);
-    rot_node.append_attribute("rev").set_value(1200000);
-    
-    auto bevel_node = effect_style_node.append_child("a:sp3d").append_child("a:bevelT");
-    bevel_node.append_attribute("w").set_value(63500);
-    bevel_node.append_attribute("h").set_value(25400);
-    
-    auto bg_fill_style_list_node = format_scheme_node.append_child("a:bgFillStyleLst");
-    
-    bg_fill_style_list_node.append_child("a:solidFill").append_child("a:schemeClr").append_attribute("val").set_value("phClr");
-    
-    grad_fill_node = bg_fill_style_list_node.append_child("a:gradFill");
-    grad_fill_node.append_attribute("rotWithShape").set_value(1);
-    
-    grad_fill_list = grad_fill_node.append_child("a:gsLst");
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(0);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:tint").append_attribute("val").set_value(40000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(350000);
-    
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(40000);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:tint").append_attribute("val").set_value(45000);
-    scheme_color_node.append_child("a:shade").append_attribute("val").set_value(99000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(350000);
-    
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(100000);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:shade").append_attribute("val").set_value(20000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(255000);
-    
-    auto path_node = grad_fill_node.append_child("a:path");
-    path_node.append_attribute("path").set_value("circle");
-    auto fill_to_rect_node = path_node.append_child("a:fillToRect");
-    fill_to_rect_node.append_attribute("l").set_value(50000);
-    fill_to_rect_node.append_attribute("t").set_value(-80000);
-    fill_to_rect_node.append_attribute("r").set_value(50000);
-    fill_to_rect_node.append_attribute("b").set_value(180000);
-    
-    grad_fill_node = bg_fill_style_list_node.append_child("a:gradFill");
-    grad_fill_node.append_attribute("rotWithShape").set_value(1);
-    
-    grad_fill_list = grad_fill_node.append_child("a:gsLst");
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(0);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:tint").append_attribute("val").set_value(80000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(300000);
-    
-    gs_node = grad_fill_list.append_child("a:gs");
-    gs_node.append_attribute("pos").set_value(100000);
-    scheme_color_node = gs_node.append_child("a:schemeClr");
-    scheme_color_node.append_attribute("val").set_value("phClr");
-    scheme_color_node.append_child("a:shade").append_attribute("val").set_value(30000);
-    scheme_color_node.append_child("a:satMod").append_attribute("val").set_value(200000);
-    
-    path_node = grad_fill_node.append_child("a:path");
-    path_node.append_attribute("path").set_value("circle");
-    fill_to_rect_node = path_node.append_child("a:fillToRect");
-    fill_to_rect_node.append_attribute("l").set_value(50000);
-    fill_to_rect_node.append_attribute("t").set_value(50000);
-    fill_to_rect_node.append_attribute("r").set_value(50000);
-    fill_to_rect_node.append_attribute("b").set_value(50000);
-    
-    theme_node.append_child("a:objectDefaults");
-    theme_node.append_child("a:extraClrSchemeLst");
-    
-    std::stringstream ss;
-    doc.print(ss);
-    return ss.str();
-}
-
-std::string write_properties_app(const workbook &wb)
-{
-    pugi::xml_document doc;
-    auto root_node = doc.append_child("Properties");
-    root_node.append_attribute("xmlns").set_value("http://schemas.openxmlformats.org/officeDocument/2006/extended-properties");
-    root_node.append_attribute("xmlns:vt").set_value("http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes");
-    
-    root_node.append_child("Application").text().set("Microsoft Excel");
-    root_node.append_child("DocSecurity").text().set("0");
-    root_node.append_child("ScaleCrop").text().set("false");
-    root_node.append_child("Company");
-    root_node.append_child("LinksUpToDate").text().set("false");
-    root_node.append_child("SharedDoc").text().set("false");
-    root_node.append_child("HyperlinksChanged").text().set("false");
-    root_node.append_child("AppVersion").text().set("12.0000");
-    
-    auto heading_pairs_node = root_node.append_child("HeadingPairs");
-    auto heading_pairs_vector_node = heading_pairs_node.append_child("vt:vector");
-    heading_pairs_vector_node.append_attribute("baseType").set_value("variant");
-    heading_pairs_vector_node.append_attribute("size").set_value("2");
-    heading_pairs_vector_node.append_child("vt:variant").append_child("vt:lpstr").text().set("Worksheets");
-    heading_pairs_vector_node.append_child("vt:variant").append_child("vt:i4").text().set(std::to_string(wb.get_sheet_names().size()).c_str());
-    
-    auto titles_of_parts_node = root_node.append_child("TitlesOfParts");
-    auto titles_of_parts_vector_node = titles_of_parts_node.append_child("vt:vector");
-    titles_of_parts_vector_node.append_attribute("baseType").set_value("lpstr");
-    titles_of_parts_vector_node.append_attribute("size").set_value(std::to_string(wb.get_sheet_names().size()).c_str());
-    
-    for(auto ws : wb)
-    {
-        titles_of_parts_vector_node.append_child("vt:lpstr").text().set(ws.get_title().c_str());
-    }
-    
-    std::stringstream ss;
-    doc.save(ss);
-    
-    return ss.str();
-}
-
-std::string write_root_rels(const workbook &)
-{
-    std::vector<relationship> relationships;
-    
-    relationships.push_back(relationship(relationship::type::extended_properties, "rId3", "docProps/app.xml"));
-    relationships.push_back(relationship(relationship::type::core_properties, "rId2", "docProps/core.xml"));
-    relationships.push_back(relationship(relationship::type::office_document, "rId1", "xl/workbook.xml"));
-    
-    return write_relationships(relationships, "");
-}
-
-std::string write_workbook(const workbook &wb)
+xml_document workbook_serializer::write_workbook() const
 {
     std::size_t num_visible = 0;
     
-    for(auto ws : wb)
+    for(auto ws : wb_)
     {
         if(ws.get_page_setup().get_sheet_state() == xlnt::page_setup::sheet_state::visible)
         {
@@ -675,41 +261,44 @@ std::string write_workbook(const workbook &wb)
     
     if(num_visible == 0)
     {
-        throw value_error();
+        throw xlnt::value_error();
     }
     
-    pugi::xml_document doc;
-    auto root_node = doc.append_child("workbook");
-    root_node.append_attribute("xmlns").set_value("http://schemas.openxmlformats.org/spreadsheetml/2006/main");
-    root_node.append_attribute("xmlns:r").set_value("http://schemas.openxmlformats.org/officeDocument/2006/relationships");
+    xml_document xml;
     
-    auto file_version_node = root_node.append_child("fileVersion");
-    file_version_node.append_attribute("appName").set_value("xl");
-    file_version_node.append_attribute("lastEdited").set_value("4");
-    file_version_node.append_attribute("lowestEdited").set_value("4");
-    file_version_node.append_attribute("rupBuild").set_value("4505");
+    xml.add_namespace("xmlns", "http://schemas.openxmlformats.org/spreadsheetml/2006/main");
+    xml.add_namespace("xmlns:r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships");
     
-    auto workbook_pr_node = root_node.append_child("workbookPr");
-    workbook_pr_node.append_attribute("codeName").set_value("ThisWorkbook");
-    workbook_pr_node.append_attribute("defaultThemeVersion").set_value("124226");
-    workbook_pr_node.append_attribute("date1904").set_value(wb.get_properties().excel_base_date == calendar::mac_1904 ? 1 : 0);
+    auto &root_node = xml.root();
+    root_node.set_name("workbook");
     
-    auto book_views_node = root_node.append_child("bookViews");
-    auto workbook_view_node = book_views_node.append_child("workbookView");
-    workbook_view_node.append_attribute("activeTab").set_value("0");
-    workbook_view_node.append_attribute("autoFilterDateGrouping").set_value("1");
-    workbook_view_node.append_attribute("firstSheet").set_value("0");
-    workbook_view_node.append_attribute("minimized").set_value("0");
-    workbook_view_node.append_attribute("showHorizontalScroll").set_value("1");
-    workbook_view_node.append_attribute("showSheetTabs").set_value("1");
-    workbook_view_node.append_attribute("showVerticalScroll").set_value("1");
-    workbook_view_node.append_attribute("tabRatio").set_value("600");
-    workbook_view_node.append_attribute("visibility").set_value("visible");
+    auto &file_version_node = root_node.add_child("fileVersion");
+    file_version_node.add_attribute("appName", "xl");
+    file_version_node.add_attribute("lastEdited", "4");
+    file_version_node.add_attribute("lowestEdited", "4");
+    file_version_node.add_attribute("rupBuild", "4505");
     
-    auto sheets_node = root_node.append_child("sheets");
-    auto defined_names_node = root_node.append_child("definedNames");
+    auto &workbook_pr_node = root_node.add_child("workbookPr");
+    workbook_pr_node.add_attribute("codeName", "ThisWorkbook");
+    workbook_pr_node.add_attribute("defaultThemeVersion", "124226");
+    workbook_pr_node.add_attribute("date1904", wb_.get_properties().excel_base_date == calendar::mac_1904 ? "1" : "0");
     
-    for(auto relationship : wb.get_relationships())
+    auto book_views_node = root_node.add_child("bookViews");
+    auto workbook_view_node = book_views_node.add_child("workbookView");
+    workbook_view_node.add_attribute("activeTab", "0");
+    workbook_view_node.add_attribute("autoFilterDateGrouping", "1");
+    workbook_view_node.add_attribute("firstSheet", "0");
+    workbook_view_node.add_attribute("minimized", "0");
+    workbook_view_node.add_attribute("showHorizontalScroll", "1");
+    workbook_view_node.add_attribute("showSheetTabs", "1");
+    workbook_view_node.add_attribute("showVerticalScroll", "1");
+    workbook_view_node.add_attribute("tabRatio", "600");
+    workbook_view_node.add_attribute("visibility", "visible");
+    
+    auto sheets_node = root_node.add_child("sheets");
+    auto defined_names_node = root_node.add_child("definedNames");
+    
+    for(auto relationship : wb_.get_relationships())
     {
         if(relationship.get_type() == relationship::type::worksheet)
         {
@@ -723,55 +312,41 @@ std::string write_workbook(const workbook &wb)
             sheet_index_string = sheet_index_string.substr(static_cast<std::string::size_type>(first_digit + 1));
             std::size_t sheet_index = static_cast<std::size_t>(std::stoll(sheet_index_string) - 1);
             
-            auto ws = wb.get_sheet_by_index(sheet_index);
+            auto ws = wb_.get_sheet_by_index(sheet_index);
             
-            auto sheet_node = sheets_node.append_child("sheet");
-            sheet_node.append_attribute("name").set_value(ws.get_title().c_str());
-            sheet_node.append_attribute("r:id").set_value(relationship.get_id().c_str());
-            sheet_node.append_attribute("sheetId").set_value(std::to_string(sheet_index + 1).c_str());
+            auto sheet_node = sheets_node.add_child("sheet");
+            sheet_node.add_attribute("name", ws.get_title());
+            sheet_node.add_attribute("r:id", relationship.get_id());
+            sheet_node.add_attribute("sheetId", std::to_string(sheet_index + 1));
             
             if(ws.has_auto_filter())
             {
-                auto defined_name_node = defined_names_node.append_child("definedName");
-                defined_name_node.append_attribute("name").set_value("_xlnm._FilterDatabase");
-                defined_name_node.append_attribute("hidden").set_value(1);
-                defined_name_node.append_attribute("localSheetId").set_value(0);
+                auto &defined_name_node = defined_names_node.add_child("definedName");
+                defined_name_node.add_attribute("name", "_xlnm._FilterDatabase");
+                defined_name_node.add_attribute("hidden", "1");
+                defined_name_node.add_attribute("localSheetId", "0");
                 std::string name = "'" + ws.get_title() + "'!" + range_reference::make_absolute(ws.get_auto_filter()).to_string();
-                defined_name_node.text().set(name.c_str());
+                defined_name_node.set_text(name);
             }
         }
     }
     
-    auto calc_pr_node = root_node.append_child("calcPr");
-    calc_pr_node.append_attribute("calcId").set_value("124519");
-    calc_pr_node.append_attribute("calcMode").set_value("auto");
-    calc_pr_node.append_attribute("fullCalcOnLoad").set_value("1");
+    auto calc_pr_node = root_node.add_child("calcPr");
+    calc_pr_node.add_attribute("calcId", "124519");
+    calc_pr_node.add_attribute("calcMode", "auto");
+    calc_pr_node.add_attribute("fullCalcOnLoad", "1");
     
-    std::stringstream ss;
-    doc.save(ss);
-    
-    return ss.str();
-}
-
-std::string workbook_serializer::write_workbook_rels(const workbook &wb)
-{
-    return write_relationships(wb.get_relationships(), "xl/");
+    return xml;
 }
     
-std::string workbook_serializer::write_defined_names(const xlnt::workbook &wb)
+bool workbook_serializer::write_named_ranges(xlnt::xml_node &named_ranges_node)
 {
-    pugi::xml_document doc;
-    auto names = doc.root().append_child("names");
-    
-    for(auto named_range : wb.get_named_ranges())
+    for(auto &named_range : wb_.get_named_ranges())
     {
-        names.append_child(named_range.get_name().c_str());
+        named_ranges_node.add_child(named_range.get_name());
     }
-    
-    std::ostringstream stream;
-    doc.save(stream);
-    
-    return stream.str();
+
+    return true;
 }
 
 } // namespace xlnt
diff --git a/source/s11n/worksheet_serializer.cpp b/source/s11n/worksheet_serializer.cpp
index 15488d13..3abdaf60 100644
--- a/source/s11n/worksheet_serializer.cpp
+++ b/source/s11n/worksheet_serializer.cpp
@@ -1,8 +1,11 @@
+#include <sstream>
+
 #include <xlnt/s11n/worksheet_serializer.hpp>
 #include <xlnt/cell/cell.hpp>
 #include <xlnt/cell/cell_reference.hpp>
 #include <xlnt/s11n/xml_document.hpp>
 #include <xlnt/s11n/xml_node.hpp>
+#include <xlnt/workbook/workbook.hpp>
 #include <xlnt/worksheet/range.hpp>
 #include <xlnt/worksheet/range_reference.hpp>
 
@@ -18,10 +21,193 @@ bool is_integral(long double d)
 } // namepsace
 
 namespace xlnt {
-
-bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector<std::string> &string_table, xml_document &xml)
+    
+bool worksheet_serializer::read_worksheet(const xml_document &xml, const std::vector<std::string> &string_table, const relationship &rel)
 {
-    ws.get_cell("A1");
+    auto &root_node = xml.root();
+    
+    auto &dimension_node = root_node.get_child("dimension");
+    std::string dimension = dimension_node.get_attribute("ref");
+    auto full_range = xlnt::range_reference(dimension);
+    auto sheet_data_node = root_node.get_child("sheetData");
+
+    if(root_node.has_child("mergeCells"))
+    {
+        auto merge_cells_node = root_node.get_child("mergeCells");
+        auto count = std::stoull(merge_cells_node.get_attribute("count"));
+        
+        for(auto merge_cell_node : merge_cells_node.get_children())
+        {
+            if(merge_cell_node.get_name() != "mergeCell")
+            {
+                continue;
+            }
+            
+            sheet_.merge_cells(merge_cell_node.get_attribute("ref"));
+            count--;
+        }
+        
+        if(count != 0)
+        {
+            throw std::runtime_error("mismatch between count and actual number of merged cells");
+        }
+    }
+    
+    for(auto row_node : sheet_data_node.get_children())
+    {
+        if(row_node.get_name() != "row")
+        {
+            continue;
+        }
+        
+        auto row_index = static_cast<row_t>(std::stoull(row_node.get_attribute("r")));
+        
+        if(row_node.get_attribute("ht") != nullptr)
+        {
+            sheet_.get_row_properties(row_index).height = std::stold(row_node.get_attribute("ht"));
+        }
+        
+        std::string span_string = row_node.get_attribute("spans");
+        auto colon_index = span_string.find(':');
+        
+        column_t min_column = 0;
+        column_t max_column = 0;
+        
+        if(colon_index != std::string::npos)
+        {
+            min_column = static_cast<column_t>(std::stoll(span_string.substr(0, colon_index)));
+            max_column = static_cast<column_t>(std::stoll(span_string.substr(colon_index + 1)));
+        }
+        else
+        {
+            min_column = static_cast<column_t>(full_range.get_top_left().get_column_index());
+            max_column = static_cast<column_t>(full_range.get_bottom_right().get_column_index());
+        }
+        
+        for(column_t i = min_column; i <= max_column; i++)
+        {
+            std::string address = xlnt::cell_reference::column_string_from_index(i) + std::to_string(row_index);
+            
+            xml_node cell_node;
+            bool cell_found = false;
+            
+            for(auto &check_cell_node : row_node.get_children())
+            {
+                if(check_cell_node.get_name() != "c")
+                {
+                    continue;
+                }
+                
+                if(check_cell_node.has_attribute("r") && check_cell_node.get_attribute("r") == address)
+                {
+                    cell_node = check_cell_node;
+                    cell_found = true;
+                    break;
+                }
+            }
+            
+            if(cell_found)
+            {
+                bool has_value = cell_node.has_child("v");
+                std::string value_string = has_value ? cell_node.get_child("v").get_text() : "";
+                
+                bool has_type = cell_node.get_attribute("t") != nullptr;
+                std::string type = has_type ? cell_node.get_attribute("t") : "";
+                
+                bool has_style = cell_node.get_attribute("s") != nullptr;
+                int style_id = has_style ? std::stoull(cell_node.get_attribute("s")) : 0;
+                
+                bool has_formula = cell_node.has_child("f");
+                bool has_shared_formula = has_formula && cell_node.get_child("f").has_attribute("t") && cell_node.get_child("f").get_attribute("t") == "shared";
+                
+                auto cell = sheet_.get_cell(address);
+                
+                if(has_formula && !has_shared_formula && !sheet_.get_parent().get_data_only())
+                {
+                    std::string formula = cell_node.get_child("f").get_text();
+                    cell.set_formula(formula);
+                }
+                
+                if(has_type && type == "inlineStr") // inline string
+                {
+                    std::string inline_string = cell_node.get_child("is").get_child("t").get_text();
+                    cell.set_value(inline_string);
+                }
+                else if(has_type && type == "s" && !has_formula) // shared string
+                {
+                    auto shared_string_index = std::stoull(value_string);
+                    auto shared_string = string_table.at(shared_string_index);
+                    cell.set_value(shared_string);
+                }
+                else if(has_type && type == "b") // boolean
+                {
+                    cell.set_value(value_string != "0");
+                }
+                else if(has_type && type == "str")
+                {
+                    cell.set_value(value_string);
+                }
+                else if(has_value && !value_string.empty())
+                {
+                    if(!value_string.empty() && value_string[0] == '#')
+                    {
+                        cell.set_error(value_string);
+                    }
+                    else
+                    {
+                        cell.set_value(std::stold(value_string));
+                    }
+                }
+                
+                if(has_style)
+                {
+                    cell.set_style_id(style_id);
+                }
+            }
+        }
+    }
+    
+    auto &cols_node = root_node.get_child("cols");
+    
+    for(auto col_node : cols_node.get_children())
+    {
+        if(col_node.get_name() != "col")
+        {
+            continue;
+        }
+        
+        auto min = static_cast<column_t>(std::stoull(col_node.get_attribute("min")));
+        auto max = static_cast<column_t>(std::stoull(col_node.get_attribute("max")));
+        auto width = std::stold(col_node.get_attribute("width"));
+        auto column_style = std::stoull(col_node.get_attribute("style"));
+        bool custom = col_node.get_attribute("customWidth") == "1";
+        
+        for(auto column = min; column <= max; column++)
+        {
+            if(!sheet_.has_column_properties(column))
+            {
+                sheet_.add_column_properties(column, column_properties());
+            }
+            
+            sheet_.get_column_properties(min).width = width;
+            sheet_.get_column_properties(min).style = column_style;
+            sheet_.get_column_properties(min).custom = custom;
+        }
+    }
+    
+    if(root_node.has_child("autoFilter"))
+    {
+        auto &auto_filter_node = root_node.get_child("autoFilter");
+        xlnt::range_reference ref(auto_filter_node.get_attribute("ref"));
+        sheet_.auto_filter(ref);
+    }
+    
+    return true;
+}
+
+bool worksheet_serializer::write_worksheet(const std::vector<std::string> &string_table, xml_document &xml)
+{
+    sheet_.get_cell("A1");
     
     xml.add_namespace("", constants::Namespaces.at("spreadsheetml"));
     xml.add_namespace("r", constants::Namespaces.at("r"));
@@ -31,10 +217,10 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
     
     auto &sheet_pr_node = root_node.add_child("sheetPr");
     
-    if(!ws.get_page_setup().is_default())
+    if(!sheet_.get_page_setup().is_default())
     {
         auto &page_set_up_pr_node = sheet_pr_node.add_child("pageSetUpPr");
-        page_set_up_pr_node.add_attribute("fitToPage", ws.get_page_setup().fit_to_page() ? "1" : "0");
+        page_set_up_pr_node.add_attribute("fitToPage", sheet_.get_page_setup().fit_to_page() ? "1" : "0");
     }
     
     auto &outline_pr_node = sheet_pr_node.add_child("outlinePr");
@@ -43,7 +229,7 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
     outline_pr_node.add_attribute("summaryRight", "1");
     
     auto &dimension_node = root_node.add_child("dimension");
-    dimension_node.add_attribute("ref", ws.calculate_dimension().to_string());
+    dimension_node.add_attribute("ref", sheet_.calculate_dimension().to_string());
     
     auto &sheet_views_node = root_node.add_child("sheetViews");
     auto &sheet_view_node = sheet_views_node.add_child("sheetView");
@@ -51,23 +237,23 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
     
     std::string active_pane = "bottomRight";
     
-    if(ws.has_frozen_panes())
+    if(sheet_.has_frozen_panes())
     {
         auto pane_node = sheet_view_node.add_child("pane");
         
-        if(ws.get_frozen_panes().get_column_index() > 1)
+        if(sheet_.get_frozen_panes().get_column_index() > 1)
         {
-            pane_node.add_attribute("xSplit", std::to_string(ws.get_frozen_panes().get_column_index() - 1));
+            pane_node.add_attribute("xSplit", std::to_string(sheet_.get_frozen_panes().get_column_index() - 1));
             active_pane = "topRight";
         }
         
-        if(ws.get_frozen_panes().get_row() > 1)
+        if(sheet_.get_frozen_panes().get_row() > 1)
         {
-            pane_node.add_attribute("ySplit", std::to_string(ws.get_frozen_panes().get_row() - 1));
+            pane_node.add_attribute("ySplit", std::to_string(sheet_.get_frozen_panes().get_row() - 1));
             active_pane = "bottomLeft";
         }
         
-        if(ws.get_frozen_panes().get_row() > 1 && ws.get_frozen_panes().get_column_index() > 1)
+        if(sheet_.get_frozen_panes().get_row() > 1 && sheet_.get_frozen_panes().get_column_index() > 1)
         {
             auto top_right_node = sheet_view_node.add_child("selection");
             top_right_node.add_attribute("pane", "topRight");
@@ -76,24 +262,24 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
             active_pane = "bottomRight";
         }
         
-        pane_node.add_attribute("topLeftCell", ws.get_frozen_panes().to_string());
+        pane_node.add_attribute("topLeftCell", sheet_.get_frozen_panes().to_string());
         pane_node.add_attribute("activePane", active_pane);
         pane_node.add_attribute("state", "frozen");
     }
     
     auto selection_node = sheet_view_node.add_child("selection");
     
-    if(ws.has_frozen_panes())
+    if(sheet_.has_frozen_panes())
     {
-        if(ws.get_frozen_panes().get_row() > 1 && ws.get_frozen_panes().get_column_index() > 1)
+        if(sheet_.get_frozen_panes().get_row() > 1 && sheet_.get_frozen_panes().get_column_index() > 1)
         {
             selection_node.add_attribute("pane", "bottomRight");
         }
-        else if(ws.get_frozen_panes().get_row() > 1)
+        else if(sheet_.get_frozen_panes().get_row() > 1)
         {
             selection_node.add_attribute("pane", "bottomLeft");
         }
-        else if(ws.get_frozen_panes().get_column_index() > 1)
+        else if(sheet_.get_frozen_panes().get_column_index() > 1)
         {
             selection_node.add_attribute("pane", "topRight");
         }
@@ -109,9 +295,9 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
     
     bool has_column_properties = false;
     
-    for(auto column = ws.get_lowest_column(); column <= ws.get_highest_column(); column++)
+    for(auto column = sheet_.get_lowest_column(); column <= sheet_.get_highest_column(); column++)
     {
-        if(ws.has_column_properties(column))
+        if(sheet_.has_column_properties(column))
         {
             has_column_properties = true;
             break;
@@ -122,9 +308,9 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
     {
         auto cols_node = root_node.add_child("cols");
         
-        for(auto column = ws.get_lowest_column(); column <= ws.get_highest_column(); column++)
+        for(auto column = sheet_.get_lowest_column(); column <= sheet_.get_highest_column(); column++)
         {
-            const auto &props = ws.get_column_properties(column);
+            const auto &props = sheet_.get_column_properties(column);
             
             auto col_node = cols_node.add_child("col");
             
@@ -140,7 +326,7 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
     
     auto sheet_data_node = root_node.add_child("sheetData");
     
-    for(auto row : ws.rows())
+    for(auto row : sheet_.rows())
     {
         row_t min = static_cast<row_t>(row.num_cells());
         row_t max = 0;
@@ -167,10 +353,10 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
         row_node.add_attribute("r", std::to_string(row.front().get_row()));
         row_node.add_attribute("spans", (std::to_string(min) + ":" + std::to_string(max)));
         
-        if(ws.has_row_properties(row.front().get_row()))
+        if(sheet_.has_row_properties(row.front().get_row()))
         {
             row_node.add_attribute("customHeight", "1");
-            auto height = ws.get_row_properties(row.front().get_row()).height;
+            auto height = sheet_.get_row_properties(row.front().get_row()).height;
             
             if(height == std::floor(height))
             {
@@ -228,14 +414,14 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
                         {
                             cell_node.add_attribute("t", "inlineStr");
                             auto inline_string_node = cell_node.add_child("is");
-                            inline_string_node.add_child("t").text().set(cell.get_value<std::string>());
+                            inline_string_node.add_child("t").set_text(cell.get_value<std::string>());
                         }
                     }
                     else
                     {
                         cell_node.add_attribute("t", "s");
                         auto value_node = cell_node.add_child("v");
-                        value_node.text().set(match_index);
+                        value_node.set_text(std::to_string(match_index));
                     }
                 }
                 else
@@ -246,22 +432,23 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
                         {
                             cell_node.add_attribute("t", "b");
                             auto value_node = cell_node.add_child("v");
-                            value_node.text().set(cell.get_value<bool>() ? 1 : 0);
+                            value_node.set_text(cell.get_value<bool>() ? "1" : "0");
                         }
                         else if(cell.get_data_type() == cell::type::numeric)
                         {
                             if(cell.has_formula())
                             {
-                                cell_node.add_child("f").text().set(cell.get_formula());
-                                cell_node.add_child("v").text().set(cell.to_string());
+                                cell_node.add_child("f").set_text(cell.get_formula());
+                                cell_node.add_child("v").set_text(cell.to_string());
                                 continue;
                             }
                             
                             cell_node.add_attribute("t", "n");
                             auto value_node = cell_node.add_child("v");
+                            
                             if(is_integral(cell.get_value<long double>()))
                             {
-                                value_node.text().set(cell.get_value<long long>());
+                                value_node.set_text(std::to_string(cell.get_value<long long>()));
                             }
                             else
                             {
@@ -269,50 +456,49 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
                                 ss.precision(20);
                                 ss << cell.get_value<long double>();
                                 ss.str();
-                                value_node.text().set(ss.str());
+                                value_node.set_text(ss.str());
                             }
                         }
                     }
                     else if(cell.has_formula())
                     {
-                        cell_node.add_child("f").text().set(cell.get_formula());
+                        cell_node.add_child("f").set_text(cell.get_formula());
                         cell_node.add_child("v");
                         continue;
                     }
                 }
                 
-                //if(cell.has_style())
+                if(cell.has_style())
                 {
-                    auto style_id = cell.get_style_id();
-                    cell_node.add_attribute("s", (int)style_id);
+                    cell_node.add_attribute("s", std::to_string(cell.get_style_id()));
                 }
             }
         }
     }
     
-    if(ws.has_auto_filter())
+    if(sheet_.has_auto_filter())
     {
         auto auto_filter_node = root_node.add_child("autoFilter");
-        auto_filter_node.add_attribute("ref", ws.get_auto_filter().to_string());
+        auto_filter_node.add_attribute("ref", sheet_.get_auto_filter().to_string());
     }
     
-    if(!ws.get_merged_ranges().empty())
+    if(!sheet_.get_merged_ranges().empty())
     {
         auto merge_cells_node = root_node.add_child("mergeCells");
-        merge_cells_node.add_attribute("count", (unsigned int)ws.get_merged_ranges().size());
+        merge_cells_node.add_attribute("count", std::to_string(sheet_.get_merged_ranges().size()));
         
-        for(auto merged_range : ws.get_merged_ranges())
+        for(auto merged_range : sheet_.get_merged_ranges())
         {
             auto merge_cell_node = merge_cells_node.add_child("mergeCell");
             merge_cell_node.add_attribute("ref", merged_range.to_string());
         }
     }
     
-    if(!ws.get_relationships().empty())
+    if(!sheet_.get_relationships().empty())
     {
         auto hyperlinks_node = root_node.add_child("hyperlinks");
         
-        for(auto relationship : ws.get_relationships())
+        for(const auto &relationship : sheet_.get_relationships())
         {
             auto hyperlink_node = hyperlinks_node.add_child("hyperlink");
             hyperlink_node.add_attribute("display", relationship.get_target_uri());
@@ -321,48 +507,45 @@ bool worksheet_serializer::write_worksheet(const worksheet ws, const std::vector
         }
     }
     
-    if(!ws.get_page_setup().is_default())
+    if(!sheet_.get_page_setup().is_default())
     {
         auto print_options_node = root_node.add_child("printOptions");
-        print_options_node.add_attribute("horizontalCentered", ws.get_page_setup().get_horizontal_centered() ? 1 : 0);
-        print_options_node.add_attribute("verticalCentered", ws.get_page_setup().get_vertical_centered() ? 1 : 0);
+        print_options_node.add_attribute("horizontalCentered", sheet_.get_page_setup().get_horizontal_centered() ? "1" : "0");
+        print_options_node.add_attribute("verticalCentered", sheet_.get_page_setup().get_vertical_centered() ? "1" : "0");
     }
     
     auto page_margins_node = root_node.add_child("pageMargins");
     
-    page_margins_node.add_attribute("left", ws.get_page_margins().get_left());
-    page_margins_node.add_attribute("right", ws.get_page_margins().get_right());
-    page_margins_node.add_attribute("top", ws.get_page_margins().get_top());
-    page_margins_node.add_attribute("bottom", ws.get_page_margins().get_bottom());
-    page_margins_node.add_attribute("header", ws.get_page_margins().get_header());
-    page_margins_node.add_attribute("footer", ws.get_page_margins().get_footer());
+    page_margins_node.add_attribute("left", std::to_string(sheet_.get_page_margins().get_left()));
+    page_margins_node.add_attribute("right", std::to_string(sheet_.get_page_margins().get_right()));
+    page_margins_node.add_attribute("top", std::to_string(sheet_.get_page_margins().get_top()));
+    page_margins_node.add_attribute("bottom", std::to_string(sheet_.get_page_margins().get_bottom()));
+    page_margins_node.add_attribute("header", std::to_string(sheet_.get_page_margins().get_header()));
+    page_margins_node.add_attribute("footer", std::to_string(sheet_.get_page_margins().get_footer()));
     
-    if(!ws.get_page_setup().is_default())
+    if(!sheet_.get_page_setup().is_default())
     {
         auto page_setup_node = root_node.add_child("pageSetup");
         
-        std::string orientation_string = ws.get_page_setup().get_orientation() == page_setup::orientation::landscape ? "landscape" : "portrait";
+        std::string orientation_string = sheet_.get_page_setup().get_orientation() == page_setup::orientation::landscape ? "landscape" : "portrait";
         page_setup_node.add_attribute("orientation", orientation_string);
-        page_setup_node.add_attribute("paperSize", (int)ws.get_page_setup().get_paper_size());
-        page_setup_node.add_attribute("fitToHeight", ws.get_page_setup().fit_to_height() ? 1 : 0);
-        page_setup_node.add_attribute("fitToWidth", ws.get_page_setup().fit_to_width() ? 1 : 0);
+        page_setup_node.add_attribute("paperSize", std::to_string(static_cast<int>(sheet_.get_page_setup().get_paper_size())));
+        page_setup_node.add_attribute("fitToHeight", sheet_.get_page_setup().fit_to_height() ? "1" : "0");
+        page_setup_node.add_attribute("fitToWidth", sheet_.get_page_setup().fit_to_width() ? "1" : "0");
     }
     
-    if(!ws.get_header_footer().is_default())
+    if(!sheet_.get_header_footer().is_default())
     {
         auto header_footer_node = root_node.add_child("headerFooter");
         auto odd_header_node = header_footer_node.add_child("oddHeader");
         std::string header_text = "&L&\"Calibri,Regular\"&K000000Left Header Text&C&\"Arial,Regular\"&6&K445566Center Header Text&R&\"Arial,Bold\"&8&K112233Right Header Text";
-        odd_header_node.text().set(header_text);
+        odd_header_node.set_text(header_text);
         auto odd_footer_node = header_footer_node.add_child("oddFooter");
         std::string footer_text = "&L&\"Times New Roman,Regular\"&10&K445566Left Footer Text_x000D_And &D and &T&C&\"Times New Roman,Bold\"&12&K778899Center Footer Text &Z&F on &A&R&\"Times New Roman,Italic\"&14&KAABBCCRight Footer Text &P of &N";
-        odd_footer_node.text().set(footer_text);
+        odd_footer_node.set_text(footer_text);
     }
     
-    std::stringstream ss;
-    doc.save(ss);
-    
-    return ss.str();
+    return true;
 }
 
 } // namespace xlnt
diff --git a/source/s11n/xml_node.cpp b/source/s11n/xml_node.cpp
index 06239c83..3b655917 100644
--- a/source/s11n/xml_node.cpp
+++ b/source/s11n/xml_node.cpp
@@ -68,13 +68,13 @@ void xml_node::add_attribute(const std::string &name, const std::string &value)
 
 bool xml_node::has_attribute(const std::string &attribute_name) const
 {
-    return std::find(attributes_.begin(), attributes_.end(),
+    return std::find_if(attributes_.begin(), attributes_.end(),
         [&](const string_pair &p) { return p.first == attribute_name; }) != attributes_.end();
 }
 
 std::string xml_node::get_attribute(const std::string &attribute_name) const
 {
-    auto match = std::find(attributes_.begin(), attributes_.end(),
+    auto match = std::find_if(attributes_.begin(), attributes_.end(),
         [&](const string_pair &p) { return p.first == attribute_name; });
     
     if(match == attributes_.end())
@@ -87,16 +87,29 @@ std::string xml_node::get_attribute(const std::string &attribute_name) const
 
 bool xml_node::has_child(const std::string &child_name) const
 {
-    return std::find(children_.begin(), children_.end(),
+    return std::find_if(children_.begin(), children_.end(),
         [&](const xml_node &n) { return n.get_name() == child_name; }) != children_.end();
 }
 
+xml_node &xml_node::get_child(const std::string &child_name)
+{
+    auto match = std::find_if(children_.begin(), children_.end(),
+        [&](const xml_node &n) { return n.get_name() == child_name; });
+    
+    if(match == children_.end())
+    {
+        throw std::runtime_error("child doesn't exist: " + child_name);
+    }
+    
+    return *match;
+}
+
 const xml_node &xml_node::get_child(const std::string &child_name) const
 {
-    auto match = std::find(children_.begin(), children_.end(),
+    auto match = std::find_if(children_.begin(), children_.end(),
         [&](const xml_node &n) { return n.get_name() == child_name; });
     
-    if(match == attributes_.end())
+    if(match == children_.end())
     {
         throw std::runtime_error("child doesn't exist: " + child_name);
     }
diff --git a/source/workbook/workbook.cpp b/source/workbook/workbook.cpp
index 92a54129..eb04670c 100644
--- a/source/workbook/workbook.cpp
+++ b/source/workbook/workbook.cpp
@@ -12,19 +12,21 @@
 #include <xlnt/common/relationship.hpp>
 #include <xlnt/common/zip_file.hpp>
 #include <xlnt/drawing/drawing.hpp>
-#include <xlnt/reader/excel_reader.hpp>
+#include <xlnt/s11n/excel_serializer.hpp>
 #include <xlnt/styles/alignment.hpp>
 #include <xlnt/styles/border.hpp>
 #include <xlnt/styles/fill.hpp>
 #include <xlnt/styles/font.hpp>
 #include <xlnt/styles/number_format.hpp>
 #include <xlnt/styles/protection.hpp>
+#include <xlnt/styles/style.hpp>
 #include <xlnt/workbook/document_properties.hpp>
+#include <xlnt/workbook/manifest.hpp>
 #include <xlnt/workbook/named_range.hpp>
+#include <xlnt/workbook/theme.hpp>
 #include <xlnt/workbook/workbook.hpp>
 #include <xlnt/worksheet/range.hpp>
 #include <xlnt/worksheet/worksheet.hpp>
-#include <xlnt/writer/excel_writer.hpp>
 
 #include "detail/cell_impl.hpp"
 #include "detail/include_pugixml.hpp"
@@ -243,22 +245,25 @@ range workbook::get_named_range(const std::string &name)
 
 bool workbook::load(std::istream &stream)
 {
-    *this = excel_reader::load_workbook(stream);
+    excel_serializer serializer_(*this);
+    serializer_.load_stream_workbook(stream);
     
     return true;
 }
     
 bool workbook::load(const std::vector<unsigned char> &data)
 {
-    *this = excel_reader::load_workbook(data);
+    excel_serializer serializer_(*this);
+    serializer_.load_virtual_workbook(data);
     
     return true;
 }
 
 bool workbook::load(const std::string &filename)
 {
-    *this = excel_reader::load_workbook(filename);
-    
+    excel_serializer serializer_(*this);
+    serializer_.load_workbook(filename);
+
     return true;
 }
 
@@ -446,13 +451,18 @@ void workbook::clear()
 
 bool workbook::save(std::vector<unsigned char> &data)
 {
-    data = save_virtual_workbook(*this);
+    excel_serializer serializer(*this);
+    serializer.save_virtual_workbook(data);
+
     return true;
 }
 
 bool workbook::save(const std::string &filename)
 {
-    return save_workbook(*this, filename);
+    excel_serializer serializer(*this);
+    serializer.save_workbook(filename);
+    
+    return true;
 }
 
 bool workbook::operator==(std::nullptr_t) const
@@ -465,7 +475,7 @@ bool workbook::operator==(const workbook &rhs) const
     return d_.get() == rhs.d_.get();
 }
 
-std::vector<relationship> xlnt::workbook::get_relationships() const
+const std::vector<relationship> &xlnt::workbook::get_relationships() const
 {
 	return d_->relationships_;
 }
@@ -570,14 +580,14 @@ void workbook::set_code_name(const std::string &/*code_name*/)
     
 }
 
-bool workbook::has_loaded_theme()
+bool workbook::has_loaded_theme() const
 {
     return false;
 }
 
-std::string workbook::get_loaded_theme()
+const theme &workbook::get_loaded_theme() const
 {
-    return "";
+    return d_->theme_;
 }
 
 std::vector<named_range> workbook::get_named_ranges() const
@@ -847,4 +857,16 @@ const manifest &workbook::get_manifest() const
     return d_->manifest_;
 }
 
+const std::vector<relationship> &workbook::get_root_relationships() const
+{
+    if(d_->root_relationships_.empty())
+    {
+        d_->root_relationships_.push_back(relationship(relationship::type::extended_properties, "rId3", "docProps/app.xml"));
+        d_->root_relationships_.push_back(relationship(relationship::type::core_properties, "rId2", "docProps/core.xml"));
+        d_->root_relationships_.push_back(relationship(relationship::type::office_document, "rId1", "xl/workbook.xml"));
+    }
+    
+    return d_->root_relationships_;
+}
+
 } // namespace xlnt
diff --git a/source/worksheet/worksheet.cpp b/source/worksheet/worksheet.cpp
index 7b3b4b2a..27a7ee05 100644
--- a/source/worksheet/worksheet.cpp
+++ b/source/worksheet/worksheet.cpp
@@ -330,7 +330,7 @@ const range worksheet::get_squared_range(column_t min_col, row_t min_row, column
     return get_range(reference);
 }
 
-std::vector<relationship> worksheet::get_relationships()
+const std::vector<relationship> &worksheet::get_relationships() const
 {
     return d_->relationships_;
 }
diff --git a/source/worksheet/worksheet_reader.cpp b/source/worksheet/worksheet_reader.cpp
index d201bf74..22ee4cde 100644
--- a/source/worksheet/worksheet_reader.cpp
+++ b/source/worksheet/worksheet_reader.cpp
@@ -1,7 +1,6 @@
 #include <xlnt/cell/cell.hpp>
 #include <xlnt/cell/cell_reference.hpp>
 #include <xlnt/common/zip_file.hpp>
-#include <xlnt/reader/worksheet_reader.hpp>
 #include <xlnt/styles/number_format.hpp>
 #include <xlnt/workbook/workbook.hpp>
 #include <xlnt/worksheet/range_reference.hpp>
@@ -14,158 +13,4 @@ namespace {
 } // namespace
 
 namespace xlnt {
-
-void read_worksheet(worksheet ws, zip_file &archive, const relationship &rel, const std::vector<std::string> &string_table)
-{    
-    pugi::xml_document doc;
-    doc.load(archive.read(rel.get_target_uri()).c_str());
-    
-    auto root_node = doc.child("worksheet");
-    
-    auto dimension_node = root_node.child("dimension");
-    std::string dimension = dimension_node.attribute("ref").as_string();
-    auto full_range = xlnt::range_reference(dimension);
-    auto sheet_data_node = root_node.child("sheetData");
-    auto merge_cells_node = root_node.child("mergeCells");
-    
-    if(merge_cells_node != nullptr)
-    {
-        int count = merge_cells_node.attribute("count").as_int();
-        
-        for(auto merge_cell_node : merge_cells_node.children("mergeCell"))
-        {
-            ws.merge_cells(merge_cell_node.attribute("ref").as_string());
-            count--;
-        }
-        
-        if(count != 0)
-        {
-            throw std::runtime_error("mismatch between count and actual number of merged cells");
-        }
-    }
-    
-    for(auto row_node : sheet_data_node.children("row"))
-    {
-        auto row_index = static_cast<row_t>(row_node.attribute("r").as_uint());
-        
-        if(row_node.attribute("ht") != nullptr)
-        {
-            ws.get_row_properties(row_index).height = row_node.attribute("ht").as_double();
-        }
-        
-        std::string span_string = row_node.attribute("spans").as_string();
-        auto colon_index = span_string.find(':');
-        
-        column_t min_column = 0;
-        column_t max_column = 0;
-        
-        if(colon_index != std::string::npos)
-        {
-            min_column = static_cast<column_t>(std::stoll(span_string.substr(0, colon_index)));
-            max_column = static_cast<column_t>(std::stoll(span_string.substr(colon_index + 1)));
-        }
-        else
-        {
-            min_column = static_cast<column_t>(full_range.get_top_left().get_column_index());
-            max_column = static_cast<column_t>(full_range.get_bottom_right().get_column_index());
-        }
-        
-        for(column_t i = min_column; i <= max_column; i++)
-        {
-            std::string address = xlnt::cell_reference::column_string_from_index(i) + std::to_string(row_index);
-            auto cell_node = row_node.find_child_by_attribute("c", "r", address.c_str());
-            
-            if(cell_node != nullptr)
-            {
-                bool has_value = cell_node.child("v") != nullptr;
-                std::string value_string = has_value ? cell_node.child("v").text().as_string() : "";
-                
-                bool has_type = cell_node.attribute("t") != nullptr;
-                std::string type = has_type ? cell_node.attribute("t").as_string() : "";
-                
-                bool has_style = cell_node.attribute("s") != nullptr;
-                int style_id = has_style ? cell_node.attribute("s").as_int() : 0;
-                
-                bool has_formula = cell_node.child("f") != nullptr;
-                bool has_shared_formula = has_formula && cell_node.child("f").attribute("t") != nullptr && std::string(cell_node.child("f").attribute("t").as_string()) == "shared";
-                
-                auto cell = ws.get_cell(address);
-                
-                if(has_formula && !has_shared_formula && !ws.get_parent().get_data_only())
-                {
-                    std::string formula = cell_node.child("f").text().as_string();
-                    cell.set_formula(formula);
-                }
-                
-                if(has_type && type == "inlineStr") // inline string
-                {
-                    std::string inline_string = cell_node.child("is").child("t").text().as_string();
-                    cell.set_value(inline_string);
-                }
-                else if(has_type && type == "s" && !has_formula) // shared string
-                {
-                    auto shared_string_index = std::stoull(value_string);
-                    auto shared_string = string_table.at(shared_string_index);
-                    cell.set_value(shared_string);
-                }
-                else if(has_type && type == "b") // boolean
-                {
-                    cell.set_value(value_string != "0");
-                }
-                else if(has_type && type == "str")
-                {
-                    cell.set_value(value_string);
-                }
-                else if(has_value && !value_string.empty())
-                {
-                    if(!value_string.empty() && value_string[0] == '#')
-                    {
-                        cell.set_error(value_string);
-                    }
-                    else
-                    {
-                        cell.set_value(std::stold(value_string));
-                    }
-                }
-                
-                if(has_style)
-                {
-                    cell.set_style_id(style_id);
-                }
-            }
-        }
-    }
-    
-    auto cols_node = root_node.child("cols");
-    
-    for(auto col_node : cols_node.children("col"))
-    {
-        column_t min = col_node.attribute("min").as_uint();
-        column_t max = col_node.attribute("max").as_uint();
-        double width = col_node.attribute("width").as_double();
-        std::size_t column_style = col_node.attribute("style").as_ullong();
-        bool custom = col_node.attribute("customWidth").as_bool();
-
-        for(auto column = min; column <= max; column++)
-        {
-            if(!ws.has_column_properties(column))
-            {
-                ws.add_column_properties(column, column_properties());
-            }
-            
-            ws.get_column_properties(min).width = width;
-            ws.get_column_properties(min).style = column_style;
-            ws.get_column_properties(min).custom = custom;
-        }
-    }
-    
-    auto auto_filter_node = root_node.child("autoFilter");
-    
-    if(auto_filter_node != nullptr)
-    {
-        xlnt::range_reference ref(auto_filter_node.attribute("ref").as_string());
-        ws.auto_filter(ref);
-    }
-}
-    
 } // namespace xlnt
diff --git a/tests/test_cell.hpp b/tests/test_cell.hpp
index 60f8a78c..52b0e931 100644
--- a/tests/test_cell.hpp
+++ b/tests/test_cell.hpp
@@ -19,11 +19,6 @@
 #include <xlnt/worksheet/worksheet.hpp>
 #include <xlnt/workbook/workbook.hpp>
 
-#include <xlnt/writer/excel_writer.hpp>
-#include <xlnt/reader/excel_reader.hpp>
-
-#include <xlnt/common/xml_tree.hpp>
-
 class test_cell : public CxxTest::TestSuite
 {
 private:
@@ -37,7 +32,8 @@ public:
     
     void test_debug()
     {
-        auto wb = xlnt::excel_reader::load_workbook("/Users/thomas/Development/xlnt/samples/formatting.xlsx");
+        xlnt::workbook wb;
+        wb.load("/Users/thomas/Development/xlnt/samples/formatting.xlsx");
         wb.save("/Users/thomas/Development/xlnt/samples/formatting-rt.xlsx");
         wb.save("/Users/thomas/Development/xlnt/samples/formatting-rt.zip");
     }
@@ -94,7 +90,6 @@ public:
         TS_ASSERT(cell.get_row() == 1);
         TS_ASSERT(cell.get_reference() == "A1");
         TS_ASSERT(!cell.has_value());
-        TS_ASSERT(cell.get_xf_index() == 0);
         TS_ASSERT(!cell.has_comment());
     }
 
@@ -179,7 +174,7 @@ public:
         auto ws = wb_guess_types.create_sheet();
         auto cell = ws.get_cell(xlnt::cell_reference(1, 1));
         
-        for(auto error_code : xlnt::cell::ErrorCodes)
+        for(auto error_code : xlnt::cell::error_codes())
         {
             cell.set_value(error_code.first);
             TS_ASSERT(cell.get_data_type() == xlnt::cell::type::error);
diff --git a/tests/test_props.hpp b/tests/test_props.hpp
index fbd97e5e..e747c124 100644
--- a/tests/test_props.hpp
+++ b/tests/test_props.hpp
@@ -3,8 +3,7 @@
 #include <iostream>
 #include <cxxtest/TestSuite.h>
 
-#include <xlnt/reader/workbook_reader.hpp>
-#include <xlnt/writer/workbook_writer.hpp>
+#include <xlnt/s11n/workbook_serializer.hpp>
 
 #include "helpers/path_helper.hpp"
 #include "helpers/helper.hpp"
@@ -16,7 +15,9 @@ public:
     {
         xlnt::zip_file archive(PathHelper::GetDataDirectory() + "/genuine/empty.xlsx");
         auto content = archive.read("docProps/core.xml");
-        auto prop = xlnt::read_properties_core(content);
+        xlnt::workbook wb;
+        xlnt::workbook_serializer serializer(wb);
+        auto prop = serializer.read_properties_core(content);
         TS_ASSERT_EQUALS(prop.creator, "*.*");
         TS_ASSERT_EQUALS(prop.last_modified_by, "Charlie Clark");
         TS_ASSERT_EQUALS(prop.created, xlnt::datetime(2010, 4, 9, 20, 43, 12));
diff --git a/tests/test_read.hpp b/tests/test_read.hpp
index fcb00f27..56a2152a 100644
--- a/tests/test_read.hpp
+++ b/tests/test_read.hpp
@@ -5,10 +5,6 @@
 
 #include <cxxtest/TestSuite.h>
 
-#include <xlnt/reader/excel_reader.hpp>
-#include <xlnt/reader/workbook_reader.hpp>
-#include <xlnt/reader/worksheet_reader.hpp>
-
 #include "helpers/path_helper.hpp"
 
 class test_read : public CxxTest::TestSuite