In Egypt during the first centuries CE, men and women would meet discreetly in their homes, in temple sanctuaries, or insolitary places to learn a powerful practice of spiritual liberation. They thought of themselves as followers of Hermes Trismegistus, the legendary master of ancient wisdom. While many of their writings are lost, those that survived have been interpreted primarily as philosophical treatises about theological topics. Wouter J. Hanegraaff challenges this dominant narrative by demonstrating that Hermetic literature was concerned with experiential practices intended for...