The Key of the Mysteries by Eliphas Levi, Aleister Crowley

Eliphas Le'vi was steeped in the Western occult tradition and a master of the Rosicrucian interpretation of the Qabalah, which forms the basis of magic as practiced in the West today. The Key of the Mysteries represents the culmination of Le'vi's thoughts and is written with subtle and delicate irony. It reveals the mysteries of religion and the secrets of the Qabalah, providing a sketch of the prophetic theology of numbers. The mysteries of nature, such as spiritualism and fluidic phantoms, are explored. Magical mysteries, the Theory of the Will with its 22 axioms are divulged. And finally it offers "the great practical secrets."

The true greatness of this work, however, lies in its ability to place occult thought firmly in Western religious traditions. For Le'vi, the study of the occult was the study of a divine science, the mathematics of God.

Alphonse Louis Constant, better know by his pen name Eliphas Levi, was a master of the traditional Rosicrucian interpretation of the Kabbalah. He was born in France in 1810, and through the offices of the parish priest, was educated for the church at Saint-Sulpice. He was later expelled from seminary for teaching doctrines contrary to those of the Roman Catholic Church. In 1824 Levi began studying the occult sciences, and wrote about magic and the Kabbalah for the next three decades. His other books include Transcendental Magic, Mysteries of the Qabalah , and The Book of Splendours.