This key to the world's esoteric traditions unlocks some of the most fascinating and closely held secrets of myth, religion, and philosophy. Unrivaled in its beauty and completeness, it distills ancient and modern teachings of nearly 600 experts. Compelling themes range from the riddle of the Sphinx and the tenets of Pythagorean astronomy to the symbolism of the pentagram, the significance of the Ark of the Covenant, and the design of the American flag. Acclaimed by Publishers Weekly as "a classic reference, dizzying in its breadth," this remarkable resource was compiled by the founder of the Philosophical Research Society. Hall examines the secrets of Isis along with arcane aspects of mystic Christianity and other religions. Fascinating surveys cover topics as diverse as Kabbalah, alchemy, cryptology, and Tarot, along with Masonry, gemology, and the identity of William Shakespeare. Sixteen pages of color plates and 100 black-and-white images by the celebrated illustrator J. Augustus Knapp illuminate this vast and indispensable encyclopedia of the occult.