What is the best book preparation for CAT?

For preparation you can refer to following reference books as per your choice: 1) How to prepare for Quantitative Aptitude for the CAT How to prepare for Data Interpretation for the CAT How to prepare for Logical Reasoning for the CAT How to prepare for Verbal Ability and Reading Comprehension for the CAT 2) Pearson Guide to Quantitative Aptitude for CAT by Nishit Sinha Pearson Guide to Quantitative Aptitude and Data Intrepretation for CAT by Nishit Sinha Pearson Guide to Verbal Ability and Logical Reasoning for CAT by Nishit Sinha There are others books like Word Power Made Easy by Norman Lewis, High School English Grammar and Composition by Wren and Martin etc to help you for your preparation. You can also join various coaching institutes like TIME, CL, IMS etc or the online coaching institutes also for concepts and mock tests. All the best!

For Quants - Get "Quantum CAT" by Sarvesh K Verma

For English - Get "Verbal ability and reading comprehension" by Arun Sharma,also get Word power Made Easy by Norman Lewis,as this book is a great guide as how to improve one's vocabulary.

For DI/LR -as per my experience you don't need any book,solve only problems and test series related to DI/LR..but if you desire you may go with Arun Sharma.