Sex magick, the practice of utilising sexual energy and sacred sex rituals as a potent force to reach higher states of consciousness, has been cloaked in secrecy for centuries, passed down as a secret doctrine through many esoteric orders, from the Knights Templar to the Rosicrucians, the Freemasons and, finally, the O.T.O. 20th century English occultist, mystic, ceremonial magician and O.T.O. leader, Aleister Crowley, believed that sexual magick was the key to unlocking the secrets of the universe. He dedicated the entire second half of his life to exploring its mysteries. This book presents the bulk of Crowley's written works on the subject.