'The man who comes back through the Door in the Wall will never be quite the same as the man who went out'. Aldous Huxley first took mescalin in 1953 and continued his experiments with hallucinogenic drugs until 1963 when, on his deathbed, he asked for and was given LSD. Huxley explores the effects of the mescalin experience, describing how the drug enabled him to discover a 'sacramental vision of reality'. He also discusses the spiritual and moral implications of the experience, demonstrating how negative emotions can transform man's perceptual Nirvana into a 'schizophrenic hell'.