"Descartes' attempt to ground the possibility of human knowledge in the existence of God was judged to be a complete failure by his contemporaries, and this remains the universal opinion of philosophers to this day, despite the fact that three and a half centuries of secular epistemology--which attempts to ground the possibility of knowledge either in the unaided human intellect or in natural processes--has failed to do any better. Further, the leading twentieth-century attempts at theistic epistemology reject both the conception of knowledge and the standards of epistemic evaluation that Descartes takes for granted. "In this book--partly an interpretation of Descartes and partly an attempt to complete his project-- the author attempts to show that a theistic epistemology incorporating Platonic and Aristotelian/Thomist elements can revitalize the Cartesian approach to the solution of the central problems of epistemology, including that most elusive of prizes--the proof of the external world." --From the author's preface