<I>Cognition</I> is a basic introductory text for college courses in the philosophy of knowledge. Joseph Owens, C.Ss.R., here expands the narrowly metaphysical treatment of knowledge given in his earlier book, <I>An Elementary Christian Metaphysics</I>, into a full-fledged epistemology. This text utilizes the traditions of Aristotle and Thomas Aquinas to reacquaint students of philosophy with a number of insights basic for a philosophic understanding of knowledge. These insights into the nature of abstraction, truth, the ground of certitude, and other major concerns of epistemology will help students clarify the approaches of contemporary philosophies.