Book Four, Parts I and II, together with Magick in Theory and Practice (Part III of Book Four), make up a complete course in Magick, with practical instruction in Yoga and mysticism. This book is the introduction and foundation upon which all further magical work will be based. Its simplicity, clarity and depth is without equal in occult literature.Part I of Book Four deals with Yoga in a very sound and methodical manner, stripping it of the mysterious and the glitter. Soberly, Crowley describes each step as a technique of mental and/or physical discipline, ultimately resulting in complete control of the will and with this, control of the physical and mental body.Part II is an encyclopedia of magical symbolism. All of the paraphernalia employed in ritual magick are carefully explained in both psychological and mystical terms. Crowley speaks with authority. He is one of the few writers on the subjects of yoga and magick who has attained Dhyana and Conversation with his Holy Guardian Angel through discipline and ritual practices. The laws and truths of the occult world which are presented here give the student on the path a sound working knowledge. Book Four is a concise, direct and honest presentation. A discussion of the fundamentals and essentials of both magick and mysticism. Illustrated. Glossary.