Book excerpt: A rigorous historical and philosophical examination of the controversial spiritual Masters who guided Madame H.P. Blavatsky in opening the world to Eastern and esoteric spirituality in the late nineteenth century. In the late nineteenth century, Russian noblewoman and occult philosopher Madame H.P. Blavatsky enthralled the world with revelations of an ancient “secret doctrine” behind the major faiths and a cosmic theology that united the insights of religion and science. Blavatsky said she was operating under the guidance of hidden Masters of wisdom, or mahatmas, who led her to reveal forgotten wisdom to modern people. The mythos of Blavatsky’s Masters left a deep mark on Western culture and spawned more than a century of debate: Were the Masters real? What did they teach? Are they reachable today? Now, independent scholar of religion Edward Abdill provides an authoritative, historically reliable, and delightfully readable study of the background and ideas of the Masters – in particular highlighting their message and its enduring relevance.