There are few books that are not only "good books" but absolutely neccessary to read. This is one of them. Julian Jaynes' theory of the evolution of the human mind is a good explanation of such different phenomenas like glossolaly, oracle, hypnosis, belief in God, belief in ghosts, obsession etc. Since in the past, hallucinations e.g. of God have been a part of man's perception of the world, and relicts of those hallucinations like superstition and religious fanatiscm that nowadays hamper mankind's progress, this book could lead mankind to a more enlightended and scientific view of the world and itself.