Western esotericism has been a pervasive presence in Western culture from late antiquity to the present day, but until recently it was largely ignored by scholars and surrounded by misconceptions and prejudice. This accessible guide provides readers with the basic knowledge and tools that will allow them to find their way in this bewildering but fascinating field. What is it that unites phenomena as diverse as ancient gnosticism and hermetism, the occult sciences of astrology, alchemy, and magic, rosicrucianism, as well as Christian theosophy, occultism, spiritualism, and the contemporary New Age spiritualities? What can the study of them teach us about our common cultural and intellectual heritage, and what is it that makes them relevant to contemporary concerns? How do we distinguish reliable historical knowledge from legends and fictions about esoteric traditions? These and many other questions are answered clearly and succinctly, so that the reader can find his way into the labyrinth of Western esotericism and out of it again.