serves as the basis for Thelema, which he said had been dictated to him by a supernatural entity named Aiwass. The Book announced the start of the Æon of Horus and declared that its followers should "Do what thou wilt": seek to align themselves with their True Will via the practice of ceremonial magic.

After the unsuccessful 1905 Kanchenjunga expedition and a visit to India and China, Crowley returned to Britain, where