Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Good for some things

I used the book for about a month to prepare for the GRE's. It was my main source of information. I found the review and tips helpful, especially for the quantitative. However, the writing samples are below par. The author believes that it is not that important to score well on this section, but in my opinion if you are writing a study guide then you should assume that your customers have high standards. Otherwise, why buy a book with the goal of a crappy essay? The book also gains you access to the online practice tests which are really helpful. The math questions seem a bit on the easy side though, compared to the actual test.