With origins extending back in time beyond the Dead Sea Scrolls, the body of writings and beliefs known as the Kabbalah has come to be increasingly recognized not only as one of the most intriguing aspects of Judaism but also as an important part of a broader mystical tradition. Here is one of the most enlightening studies ever to plumb its complex depths and range over its rich history, written by the late Gershom Scholem, the world's leading authority on the Kabbalah.