Before Gershom Scholem published “Major Trends in Jewish Mysticism” in 1941, Kabbalah had been either ignored or forgotten by 20th-century Jews. The orthodox and the secular alike were uncomfortable with Kabbalah's gnostic mythology, embarrassed by its strange books teeming with demons, magic and sex. The less known about it the better. But Scholem thought differently. To him, Kabbalah was the vibrant lost soul of a religion that modernity had made stale.