To the Most Serene Prince Ernst, Archbishop of Cologne and Elector of the Holy Roman Empire, Bishop of Liege, etc.
Martin Del Rio, priest of the Society of Jesus.
The first volume of the Magical Investigations pleased Your Highness, Prince Ernst, as I hear; I hope that this second volume will have no smaller place in your favor. It surpasses the former by its manifold variety, curiosity, and usefulness. The former contained one kind of magic; this one embraces three. Into it I have gathered whatever historians, poets, philosophers, jurists, and theologians have supplied concerning wicked acts of harmful magic, concerning vain observances, and concerning the almost infinite kinds of divinations, arranged, not inconveniently, into an order more serviceable than any up to this point.
Unless I am mistaken, men of every rank and condition will find in it something that can help them not a little, if they read attentively; and, having been helped, they will give thanks to you, Most Serene Prince, under whose auspices they will see these things brought forth into the light.
Louvain, on the Ides of September, 1599.