"Do what thou wilt shall be the whole of the Law." This oft-misunderstood phrase, which forms the basis for Crowley's practice of Magick, is found in The Book of the Law. Dictated to Crowley in Cairo between noon and 1:00p.m. on three successive days in April 1904, 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 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.