'Aleister Crowley, born Edward Alexander Crowley, and also known as both Frater Perdurabo and The Great Beast, was an influential English occultist, mystic and ceremonial magician, responsible for founding the religious philosophy of Thelema. Through this belief he came to see himself as the prophet who was entrusted with informing humanity that it was entering the new Aeon of Horus in 1904, a time when old ethical and religious systems would be replaced. Widely seen as one of the most influential occultists of all time, he was a member of the esoteric Hermetic Order of the Golden Dawn, as well as a co-founder of the A∴A∴ and eventually a leader of Ordo Templi Orientis (O.T.O.). He is known today for his magical writings, especially The Book Of The Law, the central sacred text of Thelema, although he also wrote widely on other subjects, including a large amount of fiction and poetry.
'Crowley was also a bisexual, recreational drug experimenter and social critic. In many of these roles he "was in revolt against the moral and religious values of his time", espousing a form of libertarianism based upon the rule of "Do What Thou Wilt". Because of this, he gained widespread notoriety during his lifetime, and was denounced in the popular press of the day as "the wickedest man in the world." Alongside his esoteric activities, he was an avid chess player, mountaineer, poet and playwright, and it has also been alleged that he was a spy for the British government.
'Crowley has remained an influential figure right up till this day, and in 2002, a BBC poll described him as being the seventy-third greatest Briton of all time. References to him can be found in the works of numerous writers, musicians and filmmakers, and he has also been cited as a key influence on many later esoteric groups and individuals, including Kenneth Grant, Gerald Gardner and, to some degree, Austin Osman Spare.'