DEL RIO, Martin Disquisitionum Magicarum Libri Sex, in Tres Tomos Parti…Tomos Primus ex Archiepiscopatus Moguntinensis Officina Vrsellana, impensis Iacobi König, 1606. £1500 8vo., bound in full vellum, painted to spine with additional lettering in black; yapp edges; pp. [xlix], 2-773, [xliii, index]; collation running )(8, (::)8, )()(8, A-Z8, Aa-Zz8,. Aaa-Eee8; with a series of vignettes framing title, depicting occult activities as described in the book of Exodus; text enclosed inside dual woodcut borders with printed commentary; with several headpieces, tailpieces and initials throughout; binding a little darkened and stained, with some patches of black to the upper cover; paint chipped to spine; internally remarkably clean, with even toning and the occasional small spot, stain or finger mark; corners of p. 290 and 294 repaired, not touching text; some early ink annotations to title; a very smart example. A superb early 17th century edition of Del Rio’s manual on witchcraft, with a scrap of previous owner’s manuscript notes loosely tipped in. Del Rio was born in 1551 in Antwerp, and matriculated from the Old University of Leuven at just twelve years old. In 1580, after a failed political career, he joined the Jesuit order and travelled extensively throughout Europe, teaching at the Jesuit college of Leuven and reportedly crossing paths with Michel de Montaigne - who was his second cousin. He later spent time in Austria, where he became a close confidant of the Archduke Ferdinand. Del Rio is undoubtedly best known today for this, his Magical Investigations which had initially appeared in three volumes between 1599 and 1600. Based on his knowledge of church history and the lives of the Saints, the publication is a dense and erudite work which catalogues various superstitions throughout Europe, as well as offering juridical and theological for those inquisitors and members of the clergy who were engaged with combating supposed diabolical practices. Often compared in importance to Kramer’s Malleus Maleficarum in terms of importance, the author cites Cicero, Pliny, and Apuleius within his argument, and aligns pagan notions of magic with Christian demonology. Fully endorsing the reality of witchcraft and the legitimacy of ecclesiastical and secular trials, he emphasises the devil's agency in magical practices, and despite his intention that the book be used as a refutation and heresy, it in effect provided a compendium of all of the notions which society at the time greatly feared; witches’ sabbaths, spells, charms, pacts with demons, divination, astrology and necromancy. Such was Del Rio’s success that many went on to accuse him of being a witch himself, but though he gave many accounts of witchcraft from a first-person standpoint, there is little evidence that he ever encountered supernatural forces himself. By the middle of the 17th century, Del Rio’s treatise had become a standard reference text in demonological literature, and was widely cited by theologians, inquisitors, and jurists throughout Europe. Its enduring popularity attests not only to its thoroughly-researched content, but also to the persistent fear and fascination surrounding witchcraft well into the late 17th century. In 1692 it was further cited at the Salem Witch Trials. The Oxford Historian Hugh Trevor-Roper later referred to this book as the "new Catholic Malleus", claiming that it “was the Catholic reconquest which introduced witch-burning into Flanders, and the Jesuit del Rio who would keep it up".