One's ability to stare at the monitor for 4 hours is one of key things to succeed in GMAT CAT. I bought this book to practice on the mock CATs available with it. But It's annoying to find that the S/W is compatible with Windows ver 3.21. Guess my grandpa used that version. I scanned the book/material. There is nothing unique about this book; Go for GMAT Official Guide(ETS)/Princetonreview workouts .