This is the first comprehensive and systematic analytical study of the major philosophical concepts of classical yoga. The book consists of a series of detailed discussions of the key concepts used by Patanjali in his Yoga-Sutra to describe and explain the enigma of human existence and to point a way beyond the perpetual motion of the wheel of becoming. Feuerstein's study differs from previous ones in that it seeks to free Patanjali's aphoristic statements from the accretions of later interpretations; instead, the author places the Sutra in its original context and sees it as the source of the whole edifice of classical yoga and not just as a summary of previous developments. This book will be of interest to comparative religionists, Indologists, and practitioners of yoga who wish to deepen their understanding of its philosophical basis.