Jung's landmark account of the connections between alchemy, its symbolism, the collective unconscious, and modern psychology Psychology and Alchemy is one of Jung's most influential works. In a prefatory note, he says: "In this present study of alchemy I have taken a particular example of symbol-formation, extending in all over some seventeen centuries, and have subjected it to intensive examination, linking it at the same time with an actual series of dreams recorded by a modern European not under my direct supervision and having no knowledge of what the symbols appearing in the dream might mean. It is by such intensive comparisons as this (and not one but many) that the hypothesis of the collective unconscious--of an activity in the human psyche making for the spiritual development of the individual human being--may be scientifically established." This is the second, completely revised edition. The book features 270 illustrations, drawn largely from old alchemical books and manuscripts, many of which were in Jung's personal collection.