This book was the only resource that I studied before taking the TOEFL. I did not take private lessons, and tanks to this book I could pass the test in only one attempt. If you have enough time to study and practice what the book teaches, do not worry you are going to pass.
I applied all the tecniques that the book teaches and really help, specially in reading and listening part. Speaking and writing was a little hard to me, so I needed to practice a little more, but a got 95. A score of 95 studying only this book is good. Don't you think? Also, I have to encourage that you have to read a lot, newsweek, time,discovery magazines. Whatch CNN is good for vocabulary.
Practice, practice, practice, if you do not have time for this, this is not the book for you.