: Is there an all-in-one book for CAT preparation?

There is no single all-in-one book for CAT preparation that covers all three sections in depth, so toppers use section-wise books. The closest options are solved previous-year paper books that cover VARC, DILR and QA together, such as Chapter-Wise Solved Previous Years Papers for CAT by Arun Sharma and Meenakshi Upadhyay, and Oswaal's 25 Years' Chapterwise and Topicwise Solved Papers.