In this chapter we learned about tree data structures, and how they differ from tree data types. We took the time to examine the terminology associated with trees including a visual representation of tree data structures. Next we evaluated the most common operations when working with trees and their complexity cost. Following this we created our own simple binary tree data structure class from scratch, and discussed how the recursive operations are used to traverse the tree. We examined the meaning of recursion and how to write recursive functions of your own using the Fibonacci sequence as an example of this process. Finally, we examined the various ways that tree data structures can be traversed depending on how the nodes in the tree are related to one another.