Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Neidan, or internal alchemy, spiritual alchemy was a concept in Taoist Chinese alchemy. It is a series of physical, mental, and spiritual disciplines intended to prolong the life of the body and create an immortal spiritual body that would survive after death. In Inner Alchemy, the human body becomes a laboratory in which the Three Treasures of Jing, Chi, and Shen are cultivated for the purpose of improving physical, emotional and mental health, and ultimately merging with the Tao, i.e. becoming an Immortal. In China, it is an important form of practice for most schools of Taoism.