diff --git a/README.md b/README.md
index e381ae1..1d61d33 100644
--- a/README.md
+++ b/README.md
@@ -206,8 +206,8 @@ Challenges, solutions, and unit tests are presented in the form of **IPython/Jup
 | Implement a binary search tree | [Challenge](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/bst/bst_challenge.ipynb)│[Solution](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/bst/bst_solution.ipynb) |
 | Implement depth-first search (pre-, in-, post-order) |  [Challenge](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_dfs/dfs_challenge.ipynb)│[Solution](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_dfs/dfs_solution.ipynb) |
 | Implement breadth-first search | [Challenge](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_bfs/bfs_challenge.ipynb)│[Solution](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_bfs/bfs_solution.ipynb) |
+| Determine the height of a tree | [Challenge](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_height/height_solution.ipynb)│[Solution](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_height/height_solution.ipynb) |
 | Print a tree using pre-order traversal without recursion | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
-| Determine the height of a tree | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
 | Determine the lowest common ancestor of two nodes | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
 | Transform a binary tree into a heap | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
 | Implement a right and left rotation on a tree | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
diff --git a/graphs_trees/tree_height/__init__.py b/graphs_trees/tree_height/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/graphs_trees/tree_height/height_challenge.ipynb b/graphs_trees/tree_height/height_challenge.ipynb
new file mode 100644
index 0000000..265ee50
--- /dev/null
+++ b/graphs_trees/tree_height/height_challenge.ipynb
@@ -0,0 +1,174 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>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).</i></small>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Challenge Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Determine the height of a tree.\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",
+    "* Is this a binary tree?\n",
+    "    * Yes\n",
+    "* Can we assume we already have a Node class with an insert method?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* 5 -> 1\n",
+    "* 5, 2, 8, 1, 3 -> 3"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Refer to the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_height/height_solution.ipynb).  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": true
+   },
+   "outputs": [],
+   "source": [
+    "%run ../bst/bst.py\n",
+    "%load ../bst/bst.py"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def height(node):\n",
+    "    # TODO: Implement me"
+   ]
+  },
+  {
+   "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_height.py\n",
+    "from __future__ import print_function\n",
+    "from nose.tools import assert_equal\n",
+    "\n",
+    "\n",
+    "class TestHeight(object):\n",
+    "\n",
+    "    def test_height(self):\n",
+    "        root = Node(5)\n",
+    "        assert_equal(height(root), 1)\n",
+    "        insert(root, 2)\n",
+    "        insert(root, 8)\n",
+    "        insert(root, 1)\n",
+    "        insert(root, 3)\n",
+    "        assert_equal(height(root), 3)\n",
+    "\n",
+    "        print('Success: test_height')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestHeight()\n",
+    "    test.test_height()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Solution Notebook\n",
+    "\n",
+    "Review the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/tree_height/height_solution.ipynb) for a discussion on algorithms and code solutions."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.10"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/graphs_trees/tree_height/height_solution.ipynb b/graphs_trees/tree_height/height_solution.ipynb
new file mode 100644
index 0000000..64f8fa8
--- /dev/null
+++ b/graphs_trees/tree_height/height_solution.ipynb
@@ -0,0 +1,193 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>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).</i></small>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Solution Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Determine the height of a tree.\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",
+    "* Is this a binary tree?\n",
+    "    * Yes\n",
+    "* Can we assume we already have a Node class with an insert method?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* 5 -> 1\n",
+    "* 5, 2, 8, 1, 3 -> 3"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "We'll use a recursive algorithm.\n",
+    "\n",
+    "* If the current node is None, return 0\n",
+    "* Else, return 1 + the maximum height of the left or right children\n",
+    "    \n",
+    "Complexity:\n",
+    "* Time: O(n)\n",
+    "* Space: O(log n)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "%run ../bst/bst.py"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def height(node):\n",
+    "    if node is None:\n",
+    "        return 0\n",
+    "    return 1 + max(height(node.left), \n",
+    "                   height(node.right))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Overwriting test_height.py\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%writefile test_height.py\n",
+    "from __future__ import print_function\n",
+    "from nose.tools import assert_equal\n",
+    "\n",
+    "\n",
+    "class TestHeight(object):\n",
+    "\n",
+    "    def test_height(self):\n",
+    "        root = Node(5)\n",
+    "        assert_equal(height(root), 1)\n",
+    "        insert(root, 2)\n",
+    "        insert(root, 8)\n",
+    "        insert(root, 1)\n",
+    "        insert(root, 3)\n",
+    "        assert_equal(height(root), 3)\n",
+    "\n",
+    "        print('Success: test_height')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestHeight()\n",
+    "    test.test_height()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Success: test_height\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_height.py"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.10"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/graphs_trees/tree_height/test_height.py b/graphs_trees/tree_height/test_height.py
new file mode 100644
index 0000000..cb0d3f2
--- /dev/null
+++ b/graphs_trees/tree_height/test_height.py
@@ -0,0 +1,25 @@
+from __future__ import print_function
+from nose.tools import assert_equal
+
+
+class TestHeight(object):
+
+    def test_height(self):
+        root = Node(5)
+        assert_equal(height(root), 1)
+        insert(root, 2)
+        insert(root, 8)
+        insert(root, 1)
+        insert(root, 3)
+        assert_equal(height(root), 3)
+
+        print('Success: test_height')
+
+
+def main():
+    test = TestHeight()
+    test.test_height()
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file