The magus, or celestial intelligencer; being a complete system of occult philosophy. In three books: containing the antient and modern practice of the cabalistic art, natural and celestial magic, &c. ... : Exhibiting the sciences of natural magic; alchymy, or hermetic philosophy ... the constellator

Francis Barrett’s The Magus is a foundational English-language compendium of occult philosophy, bringing together material on ceremonial magic, Kabbalah, alchemy, astrology, and related arts. Published in the early 19th century but drawing heavily on earlier sources, it became highly influential for later occultists; readers will find rituals, correspondences, magical theory, and extensive excerpts from earlier authorities.

Francis Barrett was an English occultist best known as the author of The Magus (1801), a compendium of ritual magic, astrology, alchemy, and related traditions. His book became an important source for later nineteenth-century occult revivalists and remains a key reference in the history of Western esotericism.