Nowadays, Non-linear data structures are very important in a variety of applications. The importance of trees is to make users understand any scenario in a beautiful manner. These trees whatever are discussed in the textbook are very much helpful in analyzing any real-time application and may apply this knowledge in simulating such applications. This book describes the fundamentals of Trees in the nonlinear data structures such as Binary Search Trees, AVL Trees, Red-Black Trees, Splay Trees, and B-Trees. Their operations and few examples are demonstrated. The kinds of trees discussed here are binary trees, Binary search trees, Adelson Velski Landis(AVL) Trees, Red-Black Trees, Splay Trees, and B-Trees are mentioned and their operations like searching, insertion, and deletion are also described with suitable examples.