This overview of the essentials of Yoga--understood not merely as a system of exercises but as a full-fledged spiritual tradition--is meant to both broaden and deepen the understanding of beginning students. It covers all the basic elements of this ancient discipline and philosophy of India and includes newly translated excerpts from the scriptures. Special attention is given to branches of Yoga, such as Tantra, that are of great interest to Western students but frequently misunderstood. The topics covered include:    *  The principal branches of Yoga    *  Moral principles    *  Meditation and concentration    *  Control of the breath    *  The physical exercises of Hatha Yoga    *  Diet    *  Mantras: sacred sounds of power    *  The powerful psychospiritual energy known as Kundalini    *  The transmutation of sexual energy    *  The teacher-student relationship    *  Suggestions for further reading and other resources