Born in Coruña, Spain on July 13, 1865 to a French chemist and his Spanish wife, Gérard Anaclet Vincent Encausse, the family moved to Paris in 1859, and he was raised and educated as a Frenchman. Clearly affected by his father's profession, Encausse studied medicine, and after becoming Head of the Laboratory of the Laboratory of Hypnotherapy at La Charité Hospital, in Paris; and in 1894, received his Doctorate in Medicine following his presentation on Philosophical Anatomy. Indeed, throughout his career he used his extensive knowledge of physiology, neurology, physiology and hypnotherapy to underpin his esoteric 'experimentation'. He died on October 25, 1916, when he contracted tuberculosis while working at a field hospital during World War I. He is mainly remember under his nomen esotericum, Papus. A disciple and devotee of Eliphas Lévi', he took the name he took from that esoteric author's book "Nuctemeron of Apollonius of Tyana": the word translates as 'physician'. A lifelong student of the occult, he studied Kabbalah, Tarot, Hermeticism, Magic, Theurgy and Alchemy, before co-founding his own order, the Ordre Kabbalistique de la Rose-Croix in 1888. He also founded the monthly revue l'Initiation, which, with a few quiet period, continues to this day. He claimed Maître Philippe Nizier, the Lyonnais mystic, and the Marquis Joseph Alexandre Saint-Yves d'Alveydre among his mentors. His membership expanded to a number of organizations, including the Hermetic Brotherhood of Light, and his crowning achievement, the founding of the Order Martiniste in 1887, and became Grand Hierophant of the Antient & Primitive Rites of Memphis and Mizraïm in 1913, on the death of John Yarker. A critic of organized religion, he was an enthusiastic supporter of the Église Gnostique of Jules Doinel, becoming a bishop of that church founded on the Cathar heritage in 1893. His written output was prodigious, both in his many articles for l'Initiation, La Voile d'Isis and other revues and pamphlets; and in his books, which included The Tarot of the Bohemians, The Devil and Occultism, The Science of the Mages, Contemporary Occultism, and this present book.