Swami Kripalu was arguably the most accomplished kundalini yoga master in modern times. He revived an ancient form of yoga taught to him by his guru, whom he later discovered was Lakulisha, the 28th incarnation of Shiva. He called this yoga sahaja, or natural yoga, which is also known by many other names, including surrender yoga and kundalini yoga. Kripalu practiced natural yoga for over 30 years, 10 hours a day without fail. In the end, he achieved nirbija samadhi, the highest goal of yoga. The hallmark of natural yoga is that it is spontaneous. Once the practitioner surrenders to the Divine and the life energy is awakened in the body, asanas and mudras, pranayama, sound and song, dance, thoughts and feelings all arise on their own. The practitioner merely observes what is happening. After the life energy has been awakened, the kundalini awakens by the grace of God or guru and travels up the spine, systematically piercing and evolving all the chakras. By this means, body and mind eventually become completely pure. Kripalu believed that natural yoga is the source of all other yogas and should be accorded the highest place. In this book, he combines his own experiences with what he learned from his guru, scripture, Ayurveda, and the modern sciences. He believed both in God and in science. He saw yoga as a science which has its own rules as the modern sciences have theirs. For Kripalu, the spiritual and physical merge in yoga; the evolution of the mind and body is also the evolution of the soul. This book is addressed to practitioners of both the surrendered and willful paths of yoga. It describes the asanas that occurred to Kripalu spontaneously and gives detailed instructions on how to practice them. It also includes chapters on mudra, pranayama, and all the other components of yoga practice, as well as chapters on anatomy and physiology, psychology, and ayurvedic prescriptions for the healing of thirty diseases. It is truly an encyclopedia of yoga. Includes 227 color/b&w photos.