Aleister Crowley’s system of Thelema begins with The Book of the Law, which bears the official name Liber AL vel Legis. It was written in Cairo, Egypt during his honeymoon with his new wife Rose (Rose Edith Kelly). This small book contains three chapters, each of which he claimed to have written in exactly one hour, beginning at noon, on April 8, April 9, and April 10, 1904. The writing began exactly on the stroke of the hour, and ended exactly an hour later ; it was hurried through, with no pauses of any kind. Crowley claims that he took dictation from an entity named Aiwass, whom he later identified as his own Holy Guardian Angel.
The book has three chapters, one chapter for each member of a trinity of ruling deities. Its phrasing is often ambiguous and it employs an odd, unearthly prose-poetic style which many people find beautiful. Various interpretations of its meaning are possible and Crowley wrote several commentaries during his life, some of them interpreting its verses in very different ways from his other commentaries or in ways at odds with the surface meaning.