This book was written in the 1860s, when reliable information about Hinduism was just starting to filter back to the west. Jacolliot was searching for the roots of western esoteric traditions in the far East. The high point of this book is the travelogue of his encounters in India with a fakir, who demonstrates his siddis (yogic powers) exuberantly. There is also an extensive discourse on Kabbalah, and its relationship to Eastern mystical beliefs. Jacolliot was a diffusionist, and he believed that many western esoteric traditions, specifically Egyptian, Jewish and Christian, had their origin in India.