Despite being the only official source of GRE questions, this isn't a great book. It has 6 practice tests, but they're easier than the real thing, and it does not include computer adaptive tests. Also, there's little in the way of answer explanations. The practice tests are worth taking. But don't forget to download ETS's powerprep software and take the two CATs as well.

Some of the advice is extremely obvious, but this GRE book is a good start for those who haven't taken a standardized test in a long time and need to start from the very beginning and focus on overall strategy. In general, the verbal sections are stronger than the math sections. And the practice DVD is pretty good--it does a relatively accurate job of predicting your score on the actual test.

Vocabulary is very important for the GRE, so it makes sense to buy this book and plan a long-term strategy for vocab building (5-10 words a night). A quick disclaimer: most of these words are very advanced, and for every 100 words you learn, maybe one will actually appear on the GRE. Better to start with the "Hit Parade" from "Cracking the GRE", then work your way out to the words in this book.