"The Process Church of the Final Judgement" were an unremarkable 60s apocalyptic cult founded in 1963 by Robert "The Teacher" Moore and Mary Anne "The Oracle" Maclean, two former Scientologists who changed their surnames to de Grimston after marriage.
After becoming disillusioned with Scientology, the Robert and Mary Anne started a therapy group in London called Compulsions Analysis, with the aim of helping "people fulfill themselves". Based loosely around the ideas of psychoanalyst Alfred Adler and the "techniques" of Scientology, the group quickly attracted clients over the next two and a half years through word-of-mouth. Due to intense individual therapy sessions, firm bonds were formed between these core members of The Process while bonds to those outside of the group withered, leading to the phenomenon known as social implosion: the increasing isolation from larger society lead to the development of the usual cultish devotion, unusual practices, and wholly unquestioned beliefs.
The cult started out believing that God was a perfect and infinite being, and that humanity was the polar opposite, being "a snare of confining inhibitions". This belief was later overturned after de Grimston wrote his essay The Hierarchy, which claimed that Jehovah, Satan, and Lucifer were the Three Great Gods of the Universe, and that all three should be venerated along with Christ. Reality could be interpreted as the intersection of pairs of polar opposites (Satan/Jehova and Jesus/Lucifer), and each individual was associated with one of these four archetypes by the dominant characteristics of his or her personality.
After London, the group moved to the Bahamas in 1966, and then to Xtul on the Yucatan Peninsular where they survived Hurricane Inez - an event which was influential on their beliefs about good and bad sides to the Gods of Nature, and which lead to the formation of church. The group then returned to London, and began recruiting and soliciting donations. They quickly set up chapters in the US and Europe until financial problems lead to the division of the cult into "The Omegas" (Robert and Mary Anne) and "messengers", who were sent forth to solicit donations. The cult quickly began to go down the pan, with a growing emphasis on Satan, spurious links to Charles Manson, and an oddball interest in group sex.