Internal alchemy (neidan) has been the dominant system of Daoist spiritual practice since the Song dynasty, when it was defined as the complex integration of multiple forms of Daoist self-cultivation. Its practitioners transform body energies into subtle levels of spirit and pure cosmic being, hoping to find illumination by returning to the fundamental order of the cosmos and in the process reconcile physiological training with intellectual speculation. Bringing together the best work of leading scholars in the field, this book provides, for the first time in English, a thorough and easily accessible introduction to this important tradition. The book begins with a a general survey of the body cultivation methods that form the backbone of internal alchemy and an analysis of its understanding of the human body and the terminology it employs. Next, it presents the historical development of the tradition with its major schools and a detailed discussion of key concepts, such as mind, inner nature, and destiny. Following this, presentations focus on specific practices, such as the emergence of the spirit through the top of the head, the activation of internal visions in Thunder Ritual, the sexual comingling of energies in duo-cultivation, and the body visions and transformative techniques employed by women. The volume also contains two contributions on the contemporary application of internal alchemy in China and the West. It concludes with comparative studies on Kundalini Yoga and Hermeticism.