Aleister Crowley was an English occultist, philosopher, 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. A prolific writer, he published widely over the course of his life.

The occult is a category of esoteric or supernatural beliefs and practices which generally fall outside the scope of organized religion and science, encompassing phenomena involving a 'hidden' or 'secret' agency, such as magic and mysticism. It can also refer to supernatural ideas like extra-sensory perception and parapsychology.