This oft misunderstood phrase, which forms the basis for Crowley's practice of Magick, is found in The Book of the Law. The Book of the Law is the source book and key for Crowley students and for the occult in general.

The holy text that forms the basis of Crowley's belief system, Thelema, was transmitted to him by the entity known as Aiwass over the course of three fateful April days in Cairo in 1904. With his wife Rose as the medium for what would become known as the Cairo Working, Crowley dutifully transcribed the communications on hotel stationery.

This Weiser Books edition contains the corrected text of the 1938 edition with a facsimile of Crowley's handwritten manuscript.