This is a synthesis of two one-volume works: Encyclopaedia of Psychic Science and Spence's Encyclopaedia of Occultism. But it also surpasses them by revisions and additional up-to-date information. Although I haven't read the entire two volumes, I must say that I'm impressed by the comprehensive nature of the set. It includes articles about modern occult magicians like Isaac Bonewits and doesn't leave out critics of the paranormal such as James Randi. Also check out the 4-vol. Encyclopedia of Philosophy, 24-vol. Man, Myth & Magic (Cavendish, editor), 2-vol. Encyclopedia of Freemasonry by Albert Mackey, and Bernard McGinn's series of books on Western Mysticism. All recommended.