I am a professional TOEFL prep instructor. Here is my review:
If you can only buy one book, this is the one.
However, I would*not* recommend that you buy only this book--it is not enough. You need to buy at least two other titles as well--the official "TOEFL Kit" and the "PowerPrep TOEFL" software.
First, this book does NOT have a computer test. Instead, it has some questions in the book that simulate the computer questions. Half of the tests are written for people who have to take the paper test, the other half are for people who have to take the computer test.
If you can only buy one book, you need a review of grammar and other sections of the test, and you want some practice tests, this book is your best choice. It has a lot of grammar explanations and lots of practice questions.
So, it is a great value--the price is low, and you get a lot of questions.
However, the book is not perfect. Some of the questions are old, and you will not see those types on the
TOEFL anymore. Furthermore, many of the questions are easier than the real TOEFL, especially the reading sections. Many of my students have said that the reading section is very, very hard and that they were not prepared for the real TOEFL when they took it.
In short, if you can only buy one book, this one is okay, but you really should buy official TOEFL materials so that you will be ready for the real test when you take it.