Since starting a yoga class 6 months ago I have lost 20 lbs and feel so much fitter, my posture has improved and back ache disappeared. My teacher recommended this book as a way of understanding how the exercises affect the body to bring about these benefits. It's useful and readable. If you are a lazy slob like I am, buy this book and take a class - you'll never regret it. It's a pleasant way to take a few years off your age and feel a whole lot better. I could swear I am a couple of inches taller with all that lovely stretching.