I've been constantly reading books about exercise since I'm a PT. This book is simply one of the best. If you work in the fitness industry or interested in anything about exercise or nutrition, you'll be amazed how they built a lot of things you learnt on theories that had never been proven in the first place. I actually enjoy reading this book - I'm only half way through yet - because I thought I was getting to know something about the subject, but I still felt intimidated by other Personal Trainers,their confidence and the way they act just like they know everything and beyond. About half they teach you is either never been proven or just proved to be wrong. If you are a trainer please read this book before start working with your next client.