Colin Wilson's 'Occult Trilogy‪'‬

The "Occult Trilogy" is the collective label applied to Colin Wilson's three major works on the occult: The Occult (1971); Mysteries: an Investigation into the Occult, the Paranormal and the Supernatural (1978) and Beyond the Occult (1988). They amounted to a monumental 1600 pages and have spawned many other lesser works.