Dating from about the third century A.D., the Yoga Sutra distills the essence of the physical and spiritual discipline of yoga into fewer than two hundred brief aphorisms. It is the core text for any study of meditative practice, revered for centuries for its brilliant analysis of mental states and of the process by which inner liberation is achieved. Yet its difficulties are legendary, and until now, no translation has made it fully accessible. This new translation, hailed by Yoga Journal for its "unsurpassed readability," is by one of the leading Sanskrit scholars of our time, whose Bhagavad Gita has become a recognized classic. It includes an introduction to the philosophy and psychology underlying the Yoga Sutra, the full text with explanatory commentary, and a glossary of key terms in Sanskrit and English.