Liber AL vel Legis, commonly known as The Book of the Law, is the central sacred text of Thelema. The book contains three chapters, each of which was alleged to be written down in one hour, beginning at noon, on 8 April, 9 April, and 10 April in Cairo, Egypt, in the year 1904. Crowley says that the author was an entity named Aiwass, whom he later referred to as his personal Holy Guardian Angel.

Aleister Crowley (1875 – 1947) was an English occultist, ceremonial magician, poet, painter, novelist, and mountaineer. He founded the religion of Thelema, identifying himself as the prophet entrusted with guiding humanity into the Æon of Horus in the early 20th century.