The Secret Doctrine is the seminal work of the Theosophical Movement and established Blavatsky as one of the most vocal and outspoken advocate of the Wisdom Teachings of the East. Almost every contemporary spiritual movement can trace its lineage back to the impulses expressed most consumately in this, Blavatsky's Magnum Opus. Based upon a disclosure and exposition of the hitherto unknown - and academically, quite controversial - "Stanzas of Dzyan," The Secret Doctrine elaborates on the teachings first brought to the world through the "Masters" Koot Humi and Morya and introduced in A. P. Sinnett's "Esoteric Buddhism," to which Blavatsky continuously refers and clarifies. In the two volumes (the first being Cosmogenesis) she portrays a sweeping vision of the evolution of humanity and the cosmos out of the spirit, unfolding in "rounds" and cycles of descent and reascent from and to the spirit, through cycles of reincarnation.