I purchased several books and software programs (Kaplan software, Princeton Review Prep book, Barrons, Kaplan, etc) when studying for my GMAT and by far this book was the most useful in preparing for the test. This book doesn't contain much instruction, it mainly contains old GMAT questions. I studied quite a bit and got through most of the questions by the time I took the GMAT. Couple of hints:
1. Don't start with this book. Pick up a book on test strategies from the Princeton Review or Kaplan and work through the material in those first. They will teach you test strategies and the formulas/tricks that you need to know. For example, you should memorize a list of idioms before tackling too much of the verbal..This will help you to realize why certain answers are right... The answers at the back of the book will sometimes simply say "unidiomatic".. If you don't understand what that means and what many of the common idioms are that won't mean much.
2. When you sign up for the GMAT they will send you a CD with two sample tests on it. Those sample tests contain questions that are found in this book! That can result in a slightly skewed diagnostic test score so keep that in mind. You aren't going to run into questions on the actual test that are in this book! (except for the essays - see below)
3. The essays in the back of the book appear to be the same ones that are asked on the actual test! I don't know if this is a 100% guarentee but I've heard from several people that the essay questions that they were asked on the test could be found in the back of the book. Now there are hundreds listed - but it still is valuable to spend a few hours going through them and make sure you can come up with an approach to them.
3. This book has tons of problems, so you may start to forget what you've done and what you haven't. When working through the problems I marked problems that I got wrong the first time around. About a month later I went back through the book and re-did those problems to see if I could do them. Trust me - you won't remember most of the problems the second time around if you're studying for the test over a several month time period like I did.
Have fun preparing! If you have any questions about other books or the GMAT itself feel free to email.. I feel like I've been through an exhaustive process (GMAT and application process) and would be happy to help anyone who needs it. I did pretty well on my GMAT too.
by Steven Schneider from Fairfax Station, VA USA