I had taken the GRE but was disappointed with my math score, so I picked up this book based on the great reviews. This has a very thorough review of various math concepts (arithmetic, algebra, geometry, and some questions specific to certain standardized tests, such as quantitative comparisons) with a lot of practice problems. I felt that a shining point of this book was the diagnostic test at the beginning of each section; it helps you narrow down your focus to the concepts you don't know, and includes page numbers to direct you to the correct section. Definitely take your time with this book to get the maximum benefit from it.