diff --git a/sorting_searching/merge_into/__init__.py b/sorting_searching/merge_into/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/sorting_searching/merge_into/merge_into_challenge.ipynb b/sorting_searching/merge_into/merge_into_challenge.ipynb
new file mode 100644
index 0000000..63fdd95
--- /dev/null
+++ b/sorting_searching/merge_into/merge_into_challenge.ipynb
@@ -0,0 +1,178 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Challenge Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Given sorted arrays A, B, merge B into A in sorted order.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)\n",
+    "* [Solution Notebook](#Solution-Notebook)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Does A have enough space for B?\n",
+    "    * Yes\n",
+    "* Can the inputs have duplicate array items?\n",
+    "    * Yes\n",
+    "* Can we assume the inputs are valid?\n",
+    "    * No\n",
+    "* Does the inputs also include the actual size of A and B?\n",
+    "    * Yes\n",
+    "* Can we assume this fits memory?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* A or B is None -> Exception\n",
+    "* index of last A or B < 0 -> Exception\n",
+    "* A or B is empty\n",
+    "* General case\n",
+    "    * A = [1,  3,  5,  7,  9,  None,  None,  None]\n",
+    "    * B = [4,  5,  6]\n",
+    "    * A = [1, 3, 4, 5, 5, 6, 7, 9]"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Refer to the [Solution Notebook]().  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "class Array(object):\n",
+    "\n",
+    "    def merge_into(self, source, dest, source_end_index, dest_end_index):\n",
+    "        # TODO: Implement me\n",
+    "        pass"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "**The following unit test is expected to fail until you solve the challenge.**"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "# %load test_merge_into.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestArray(object):\n",
+    "\n",
+    "    def test_merge_into(self):\n",
+    "        array = Array()\n",
+    "        assert_raises(TypeError, array.merge_into, None, None, None, None)\n",
+    "        assert_raises(ValueError, array.merge_into, [1], [2], -1, -1)\n",
+    "        a = [1, 2, 3]\n",
+    "        assert_equal(array.merge_into(a, [], len(a), 0), [1, 2, 3])\n",
+    "        a = [1, 2, 3]\n",
+    "        assert_equal(array.merge_into(a, [], len(a), 0), [1, 2, 3])\n",
+    "        a = [1,  3,  5,  7,  9,  None,  None,  None]\n",
+    "        b = [4,  5,  6]\n",
+    "        expected = [1, 3, 4, 5, 5, 6, 7, 9]\n",
+    "        assert_equal(array.merge_into(a, b, 5, len(b)), expected)\n",
+    "        print('Success: test_merge_into')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestArray()\n",
+    "    test.test_merge_into()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Solution Notebook\n",
+    "\n",
+    "Review the [Solution Notebook]() for a discussion on algorithms and code solutions."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.5.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/sorting_searching/merge_into/merge_into_solution.ipynb b/sorting_searching/merge_into/merge_into_solution.ipynb
new file mode 100644
index 0000000..2df970e
--- /dev/null
+++ b/sorting_searching/merge_into/merge_into_solution.ipynb
@@ -0,0 +1,276 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Solution Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Given sorted arrays A, B, merge B into A in sorted order.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Does A have enough space for B?\n",
+    "    * Yes\n",
+    "* Can the inputs have duplicate array items?\n",
+    "    * Yes\n",
+    "* Can we assume the inputs are valid?\n",
+    "    * No\n",
+    "* Does the inputs also include the actual size of A and B?\n",
+    "    * Yes\n",
+    "* Can we assume this fits memory?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* A or B is None -> Exception\n",
+    "* index of last A or B < 0 -> Exception\n",
+    "* A or B is empty\n",
+    "* General case\n",
+    "    * A = [1,  3,  5,  7,  9,  None,  None,  None]\n",
+    "    * B = [4,  5,  6]\n",
+    "    * A = [1, 3, 4, 5, 5, 6, 7, 9]"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "<pre>\n",
+    "                     i                 k\n",
+    "A = [1,  3,  5,  7,  9,  None,  None,  None]\n",
+    "             j\n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A[k] = max(A[i], B[j])\n",
+    "                     i                 k\n",
+    "A = [1,  3,  5,  7,  9,  None,  None,  9]\n",
+    "             j\n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A[k] = max(A[i], B[j])\n",
+    "                 i              k       \n",
+    "A = [1,  3,  5,  7,  9,  None,  7,  9]\n",
+    "             j\n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A[k] = max(A[i], B[j])\n",
+    "             i           k              \n",
+    "A = [1,  3,  5,  7,  9,  6,  7,  9]\n",
+    "             j\n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A[k] = max(A[i], B[j])\n",
+    "             i       k                  \n",
+    "A = [1,  3,  5,  7,  5,  6,  7,  9]\n",
+    "         j    \n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A[k] = max(A[i], B[j])\n",
+    "         i       k                      \n",
+    "A = [1,  3,  5,  5,  5,  6,  7,  9]\n",
+    "         j    \n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A[k] = max(A[i], B[j])\n",
+    "         i   k                          \n",
+    "A = [1,  3,  4,  5,  5,  6,  7,  9]\n",
+    "     j        \n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A[k] = max(A[i], B[j])\n",
+    "        ik                              \n",
+    "A = [1,  3,  4,  5,  5,  6,  7,  9]\n",
+    "             \n",
+    "B = [4,  5,  6]\n",
+    "\n",
+    "---\n",
+    "\n",
+    "A = [1, 3, 4, 5, 5, 6, 7, 9]\n",
+    "\n",
+    "</pre>\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(m + n)\n",
+    "* Space: O(1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "class Array(object):\n",
+    "\n",
+    "    def merge_into(self, source, dest, source_end_index, dest_end_index):\n",
+    "        if source is None or dest is None:\n",
+    "            raise TypeError('source or dest cannot be None')\n",
+    "        if source_end_index < 0 or dest_end_index < 0:\n",
+    "            raise ValueError('end indices must be >= 0')\n",
+    "        if not source:\n",
+    "            return dest\n",
+    "        if not dest:\n",
+    "            return source\n",
+    "        source_index = source_end_index - 1\n",
+    "        dest_index = dest_end_index - 1\n",
+    "        insert_index = source_end_index + dest_end_index - 1\n",
+    "        while dest_index >= 0:\n",
+    "            if source[source_index] > dest[dest_index]:\n",
+    "                source[insert_index] = source[source_index]\n",
+    "                source_index -= 1\n",
+    "            else:\n",
+    "                source[insert_index] = dest[dest_index]\n",
+    "                dest_index -= 1\n",
+    "            insert_index -= 1\n",
+    "        return source"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Overwriting test_merge_into.py\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%writefile test_merge_into.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestArray(object):\n",
+    "\n",
+    "    def test_merge_into(self):\n",
+    "        array = Array()\n",
+    "        assert_raises(TypeError, array.merge_into, None, None, None, None)\n",
+    "        assert_raises(ValueError, array.merge_into, [1], [2], -1, -1)\n",
+    "        a = [1, 2, 3]\n",
+    "        assert_equal(array.merge_into(a, [], len(a), 0), [1, 2, 3])\n",
+    "        a = [1, 2, 3]\n",
+    "        assert_equal(array.merge_into(a, [], len(a), 0), [1, 2, 3])\n",
+    "        a = [1,  3,  5,  7,  9,  None,  None,  None]\n",
+    "        b = [4,  5,  6]\n",
+    "        expected = [1, 3, 4, 5, 5, 6, 7, 9]\n",
+    "        assert_equal(array.merge_into(a, b, 5, len(b)), expected)\n",
+    "        print('Success: test_merge_into')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestArray()\n",
+    "    test.test_merge_into()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Success: test_merge_into\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_merge_into.py"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.5.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/sorting_searching/merge_into/test_merge_into.py b/sorting_searching/merge_into/test_merge_into.py
new file mode 100644
index 0000000..b0e7d84
--- /dev/null
+++ b/sorting_searching/merge_into/test_merge_into.py
@@ -0,0 +1,27 @@
+from nose.tools import assert_equal, assert_raises
+
+
+class TestArray(object):
+
+    def test_merge_into(self):
+        array = Array()
+        assert_raises(TypeError, array.merge_into, None, None, None, None)
+        assert_raises(ValueError, array.merge_into, [1], [2], -1, -1)
+        a = [1, 2, 3]
+        assert_equal(array.merge_into(a, [], len(a), 0), [1, 2, 3])
+        a = [1, 2, 3]
+        assert_equal(array.merge_into(a, [], len(a), 0), [1, 2, 3])
+        a = [1,  3,  5,  7,  9,  None,  None,  None]
+        b = [4,  5,  6]
+        expected = [1, 3, 4, 5, 5, 6, 7, 9]
+        assert_equal(array.merge_into(a, b, 5, len(b)), expected)
+        print('Success: test_merge_into')
+
+
+def main():
+    test = TestArray()
+    test.test_merge_into()
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file