A waste of money and time. So many mistakes in the book that it almost takes away from anything you learn. I did need a refresher on my math before the GMAT, but this book goes far beyond what will ever appear on the test which was a waste of time. Add to that all the typos in the practice questions and you have a very ineffective study guide.
Horrible study tool!.. Studied this book for a month before taking the GMAT, and I was not adequately prepared for the quantitative section of the test. I scored "ok" on the GMAT and was accepted to grad school in SPITE of this book!