The Marquis Alexandre Saint-Yves d'Alveydre (1842-1909) was a key figure of French esoteric tradition whose revelations about the kingdom of Agarttha had a profound influence on the young René Guénon. Saint-Yves' ideas for theocratic government affected the course of politics during the early twentieth century, serving as a model for a number of political groups.His magnum opus, The Archaeometer, presents a reconstructive analysis of the metaphysical system used by all esoteric Traditions to encode their sacred knowledge through mathematical and geometrical principles into religious art, music, and literature. Its scientific reconstruction of this primordial Western cabala holds a key to the system of universal order behind all natural laws.In the words of the author: "The Archaeometer is the instrument used by the Ancients for the formation of the esoteric myths of all religions. It is the canon of ancient Art in its various architectural, musical, poetic, and theogonic manifestations. It is the Heaven that speaks: every star, every constellation becomes a letter or a phrase, or a divine name lighting the ancient traditions of all peoples with a new day."