There are several great books available to prepare for M.Tech Computer Science. Some of the best books are Computer Organization and Design: The Hardware/Software Interface by David A. Patterson and John L. Hennessy, Data Structures and Algorithms Made Easy by Narasimha Karumanchi, Operating System Concepts by Abraham Silberschatz, Peter B. Galvin, and Greg Gagne, Introduction to the Theory of Computation by Michael Sipser, Fundamentals of Database Systems by Ramez Elmasri and Shamkant B. Navathe, and Fundamentals of Database Systems by Ramez Elmasri and Shamkant B. Navathe. You can select based on the Computer Science syllabus and topics mentioned in the same. We hope this information was helpful to you.