Helena Petrovna Blavatsky (1831–1891) was a Russian-German occultist and principal founder of the Theosophical Society (1875). Her major works — Isis Unveiled (1877) and The Secret Doctrine (1888) — remain foundational texts of the Theosophical tradition. Blavatsky was among the first Western writers to systematically present Eastern philosophical and spiritual teachings to a global audience. Her collected writings comprise over fourteen volumes.