Advanced Data Structures is a core subject in Computer Science. It includes a solid introduction to algorithms, data structures and uses C++ syntax and structure in the design of data structures. This textbook helps the students to make the transition from fundamentals of data structures to an advanced level of data structures and their applications. At the beginning, the non-linear data structures such as trees and graphs are discussed in the first two units. In the third unit, the concept of hashing is discussed. In this, the hashing methods, collision handling techniques, concept of dictionary and skip lists are discussed. Next two units are based on search trees and multiway trees. These are basically the advanced level tree structures such as AVL trees, Optimal Binary Search Trees (OBST), B trees, B+ trees, Trie trees, Red-black trees, KD trees and AA trees. Sufficient number of examples and programming illustrations are supported for better understanding of the complex concepts in the simplest manner. Finally, the file organization is discussed, in which various file organization techniques and implementation is illustrated. The objective of this book is to enable students to have the much-needed foundation for advanced technical skill, leading to better problem-solving approach.