CAT

There are plenty of books in the market. It has been found among students that they are referring a lot of books, online material, notes etc. For the preparation. On the contrary, what is needed most is- conceptual clarity, pattern, and understanding. Although, sometimes, it is helpful for the students to prepare with many books, in order to get quick tips and tricks but having more books, you may confused. I never disputed the fact that books are not important. These are highly recommendable. On the other hand I believe that read one authentic source or material or book many times, rather reading many books on single time. As far as MBA preparation is concerned, there are three kind of skills are mostly measured such as - Verbal, quantitative and reasoning. Different tests have different pattern, skills needed and etc. So you should keep in mind the following things and should refer following material. For the fundamental clarity of quantitative and grammar - go through the CBSE board books. You will get much benefits in understanding and getting huge out of it. It could be easy for you to make more nuanced approach in standard questions. Verbal part consist of - Sentence correction, fill in the blanks, sentence equivalence etc. , where one needs a great deal of understanding in grammar. Either one can refer an ideal book like Wren and martin or other of CBSE book. Reading is pivotal in all the tests such as, so you must have great command on reading. This can be improved easily if you are in to habit of reading papers and magazines.
Best of luck!