The importance of Francis Suarez is more and more being recognized. Suarez was so successful in writing a systematic presentation of metaphysics - that was not a commentary on Aristotle - that his work was used as a university textbook and as a model for aspiring metaphysicians for over a hundred years, not only by his fellow Jesuits, but also, perhaps to an even greater extent, by Protestant scholastic philosophers and theologians. Suarez's influence was not restricted to the scholastic tradition; rather, it extended, both through that tradition and independently of it, into the main currents of modern thought. It can be detected in Descartes, Leibniz, Wolf and, ultimately, in Kant himself. So pervasive was Suarez's influence on modern thought, that Alasdair Maclntyre has called Suarez the first truly modern philosopher. Even apart from its historical influence, Suarez's work remains important for its intrinsic merit. It could be very reasonably argued that Suarez produced the most perfect incarnation of the type of realistic metaphysics initiated by Aristotle. As long, therefore, as Aristotelianism remains a live option for philosophers, Suarez's work will remain valuable to those engaged in the philosophical enterprise. Disputation XV, which deals with the formal principle of the nature of material substances, that is, their substantial form, is central to Suarez's presentation of Aristotelian realism. In the Disputation Suarez defended the view, contrary to both dualism and materialism, that material objects are constituted by two co-principles, primary matter and substantial form. The two translators, Jeremiah Reedy and John Kronen, have produced a clear and readable translation of this Disputation central to Suarezian metaphysics. In his introduction and notes to the translation Kronen clearly explains the metaphysics of substantial form and clarifies many of the problems which Suarez discusses.
