Turbulence (a new perspective for pilots), by Peter F. Lester,
http://www.amazon.com/Turbulence-Per.../dp/088487141X
Jeppesen says "it is the most comprehensive, understandable book available on turbulence as it pertains to aviation. It will help you recognize the conditions that cause turbulence, so the effects can be avoided or minimized. This book provides answers to questions such as: What is turbulence? What does it look like? How long does it last? What causes it? Where is it found? What are its indicators? What are its typical dimensions and intensities? "

I say, it was much more than that. Its coverage ranged from wind eddies around barns to upper level standing gravity waves and the flow of air around the jet stream to how to spot turbulence and the conditions that are right for it. Provides great insight many aspects of weather.

As both an international widebody captain for a major airline, and a glider pilot, I recommend this book for pilots of any aircraft type.

It's not a test prep book, but it will help you understand the atmosphere and also help by understanding why clouds are shaped the way they are, thus indicating what's going on there. Something every glider pilot can benefit from (well, every pilot - period, for that matter).