About 20 million Americans practice some form of Yoga. Yet Yoga's original purpose-as a path to inner freedom and enlightenment-is embodied by only a few. The author of The Yoga Tradition and other Yoga texts introduces this growing market to the mental and physical disciplines of this ancient philosophy for living. From Yoga's origins and evolution into many schools to the principles that unite them all, here is the perfect primer on Yoga and its authentic practice.