Isis Unveiled: A Master-Key to the Mysteries of Ancient and Modern Science and Theology, published in 1877, is a book of esoteric philosophy and Helena Petrovna Blavatsky's first major work and a key text in her Theosophical movement. The work has often been criticized as a plagiarized occult work, with scholars noting how Blavatsky extensively copied from many sources popular among occultists at the time. Isis Unveiled is nevertheless also understood by modern scholars to be a milestone in the history of Western esotericism. Overview The work was originally entitled The Veil of Isis, a title which remains on the heading of each page, but had to be renamed once Blavatsky discovered that this title had already been used for an 1861 Rosicrucian work by W. W. Reade. Isis Unveiled is divided into two volumes. Volume I, The "Infallibility" of Modern Science, discusses occult science and the hidden and unknown forces of nature, exploring such subjects as forces, elementals, psychic phenomena, and the Inner and Outer Man. Volume II, Theology, discusses the similarity of Christian scripture to Eastern religions such as Buddhism, Hinduism, the Vedas, and Zoroastrianism. It follows the Renaissance notion of prisca theologia, in that all these religions purportedly descend from a common source; the ancient "Wisdom-Religion". Blavatsky writes in the preface that Isis Unveiled is "a plea for the recognition of the Hermetic philosophy, the anciently universal Wisdom-Religion, as the only possible key to the Absolute in science and theology." Isis Unveiled is argued by many modern scholars such as Bruce F. Campbell and Nicholas Goodrick-Clarke to be a milestone in the history of Western Esotericism. Blavatsky gathered a number of themes central to the occult tradition—perennial philosophy, a Neo-Platonic emanationist cosmology, adepts, esoteric Christianity—and reinterpreted them in relation to current developments in science and new knowledge of non-Western faiths. In doing so, Isis Unveiled reflected many contemporary controversies—such as Darwin's theories on evolution and their impact on religion—and engaged in a discussion that appealed to intelligent individuals interested in religion but alienated from conventional Western forms. Blavatsky's combination of original insights, backed by scholarly and scientific sources, accomplished a major statement of modern occultism's defiance of materialist science. In later theosophical works some of the doctrines originally stated in Isis Unveiled appeared in a significantly altered form, drawing out confusion among readers and even causing some to perceive contradiction. Specifically, the few and—according to many—ambiguous statements