Aquinas occupies an extremely important position in the western philosophical tradition. His work contains influential contributions in logic, metaphysics, theory of knowledge, ethics and philosophy of religion, and his commentaries on Aristotle played a major role in the incorporation of the philosophy of Aristotle into the understanding of Christian doctrine and into western culture at large. Yet many people find it difficult to begin the study of Aquinas's work, daunted by its volume and by its being worked out within in the context of Catholic doctrine, which must now be obscure to most readers. This book can help rectify this.