Helena P. Blavatsky's The Secret Doctrine, Vol. I: Cosmogenesis (1888) presents an esoteric cosmology synthesizing ancient Eastern philosophy, occultism, and science to explain the universe's origin and evolution. It outlines a cyclical universe based on Hindu concepts of active manvantaras and passive pralayas, emphasizing a fundamental, eternal spiritual reality behind all phenomena. The Secret Doctrine serves as a foundational text for Theosophy, aiming to reveal the hidden "wisdom-religion" or universal, ancient, and esoteric truths.