The document is a comprehensive question bank for the course CS8391 Data Structures at Anna University, authored by Dr. P. Subathra. It covers various topics such as linear data structures (arrays, linked lists, stacks, and queues), non-linear data structures (trees, binary search trees, AVL trees, and B-trees), and includes algorithms, coding exercises, and theoretical explanations. The content is structured into units focusing on different data structures and their operations, alongside multiple coding and algorithmic questions.