The book is primarily intended to be used by undergraduate students who are familiar with the concepts of programming and 'C' programming language. The topics chosen are centered around standard data structures syllabus for any undergraduate curriculum. The book also covers the syllabus of the paper "Data Structure" for "A" and "B" level courses of DOEACC. Our presentation style is based on our belief in progressing from the concrete to the abstract. We have taken special care while introducing new concepts and while proceeding from simple to more complex ideas. Examples are numerous and they have been selected carefully. Each chapter ends with a collection of all the ideas introduced and developed therein. Exercises are exhaustive and they have varied complexities. A large collection of various objective type questions (with answers) has been provided in this book.