In the present period of soul-searching, conflict and reconciliation, many people are turning to the ancient Indian classics of spiritual development and psychology for illumination and guidance. Prominent among these classics is the collection of aphorisms called the Yoga Sutras of Patanjali, which offer a systematic exposition of principles and practices successfully followed over the course of 1000 years before the Christian era.This comprehensive and up-to-date study, with its preliminary mystical explanations of themes in the Rig Veda, Upanishads and early Buddhism, will hopefully make the substance of this ancient guide to spirituality more immediately accessible and illuminating for our modern times.