Aleister Crowley (1875-1947), born Edward Alexander Crowley, was an influential English occultist, mystic, ceremonial magician, and poet, notorious for his esoteric writings and unconventional lifestyle. He proclaimed himself as the prophet entrusted with guiding humanity into the Æon of Horus, an era of self-realization and personal sovereignty. His written works blend a variety of disciplines including Eastern and Western mysticism, ceremonial magic, and psychology, solidifying his role as one of the seminal figures in modern Western occultism. Among his vast literary output, 'The Book of the Law', Crowley's central sacred text, is particularly significant, as it served as the foundation of his philosophical system, Thelema. In his exploration of the complex realm of psychoactive substances, 'The Psychology Behind Hashish' provides insight into Crowley's interest in the effects of drugs on the human mind and consciousness. His literary style often fluctuated between the didactic to the arcane, reflecting his complex system of magick and Thelemic principles. His influence continues to be felt in various fields of mystical and magical practice, as well as within pop culture and literature, despite the controversial aspects of his life and works.