The Book of Dzyan is a foundational, esoteric text that serves as the basis for Helena Petrovna Blavatsky’s 1888 magnum opus, The Secret Doctrine. Blavatsky claimed this work was an ancient manuscript, likely of Tibetan origin, written in the "Senzar" language, and containing the secret wisdom of the world. Essentially, the Book of Dzyan is a cryptic, symbolic text outlining a theory of cosmic and human evolution that challenges modern scientific and religious perspectives, favoring a cyclical, ancient, and "occult" history.