This unusual grimoire was known to exist only in the form of several nineteenth century manuscripts, which are said to have been transcribed by Frederick Hockley from "an ancient Latin manuscript," dated 1519. However, recent research suggests that these manuscripts were written by Hockley himself, although he obviously made use of a variety of earlier sources. Curiously the work known as 'The Secret Grimoire of Turiel,' seems to have been derived from it, although A Complete Book of Magic Science is lengthier and contains much additional material. Hockley made several manuscripts of A Complete Book of Magic Science in the 1830s or 1840s, and one of these, complete with beautiful color drawings of the sigils, magical circles etc., was recently discovered. It is from this Hockley manuscript, that this edition has been prepared. Hockley (1809-1885) was a dedicated occultist and Freemason, who in later in life joined the Societas Rosicruciana in Anglia and other esoteric fraternities, although his real passion lay in ceremonial magick of the type that involved contact with Spirits. He worked for the bookseller John Denley, who knew Francis Barrett and had provided him with many of the books that he used in compiling The Magus. Hockley himself put together a huge library on the occult, and sought out and copied a number of manuscripts and grimoires that he found hidden in collections around England. After his death Hockley's library was dispersed, and a number of his manuscripts were obtained and used by members of the Hermetic Order of the Golden Dawn, the famous magical group in which Aleister Crowley started his career. There is a persistent speculation that Hockley was the source of the famous 'cipher manuscripts' from which the basic structure and rituals of Order were drawn and one of the groups founders, W. Wynn Westcott, not only wrote that Hockley's manuscripts were "highly esteemed," and claimed him as one of the Order's prominent Adepts. This First Edition of A Complete Book of Magic Science faithfully reproduces the text and diagrams of Hockley's manuscript. It is prefaced with an Introduction by Dietrich Bergman, who has also carefully analyzed the text in comparison to that of 'The Secret Grimoire of Turiel,' and annotated it accordingly.