Good supplemental reading, but rely on the PMBOK!
This book provided some good information and presented some of the stodgy content of the PMBOK in a matter-of-fact approach. I would not rely on this book, however, as it delves into a lot of material not covered on the exam. If you get caught up in the complex formulas in the CAPM guide, you are likely to miss the key 4 or 5 formulas that the CAPM exam actually covers. I passed the exam, although I relied principally on the PMBOK. For an entry-level exam such as the CAPM, the PMBOK is really all you need. For those with little to no PM experience, a couple of supplemental readings such as this one may be helpful. Good luck!