Throughout history there have been societies of closed membership and covert purpose. In this comprehensive work, David Barrett explores these movements from their roots in the carliest civilizations to the present day. Marked by carefully graded and progressive teachings leading to hidden and unique truths, access only for selected individuals, and the practice of rituals of which nonmembers are not privy, these societies--from the Knights Templar and the Gnostics to the Cathars, Rosicrucians, and Freemasons--promise the initiated a realm of personal benefits beyond their reach, and even their comprehension. Barrett unlocks the ancient widsom of the Mediterranean civilizations, which formed the basis of many groups and whose tenets, principles, and esoteric religious beliefs surfaced in medieval times, and describes in detail how they survive in secret societies today.