Guido Roberts, a young man in London in 1967, is fascinated by the libertine philosophy of Aleister Crowley, the notorious Victorian practitioner of the Black Arts. Crowley's use of hallucinogenic and mind-altering drugs like mescaline, hashish and heroin, make him a prophet, Guido believes, for the 20th century. Guido becomes entangled in a growing enthusiasm for the occult and for witchcraft, as young English feminists reclaim witchcraft as a form...