The Secret Doctrine, the Synthesis of Science, Religion and Philosophy, a book originally published as two volumes in 1888, is Helena Blavatsky's magnum opus. It was an influential example of the revival of interest in esoteric and occult ideas in the modern age, in particular because of its claim to reconcile ancient eastern wisdom with modern science. The book purports to explain the origin and evolution of the universe itself. Helena Petrovna Blavatsky (1831 -1891) was a Russian occultist, spirit medium, and author who co-founded the Theosophical Society in 1875. She gained an international following as the leading theoretician of Theosophy, the esoteric religion that the society promoted.