Aquinas’ discussions of moral issues are extensive and range well beyond the narrowly defined set of issues in the modern tradition of moral philosophy. This volume explores the ethical dimensions of a wide selection of philosophical and theological topics in Aquinas’ texts. It covers topics central to ethics, such as happiness, moral virtue and natural law, as well as related topics pertaining to the metaphysical basis of Aquinas’ account of goodness, the ramifications of his ethical concerns for his philosophy of language, and the significance of his philosophical psychology for his ethics. The volume is divided into three sections focusing, respectively, on issues concerning moral theory and moral theology, moral psychology and practical reason, and moral theory in philosophy of language and metaphysics. The contributing authors bring to these issues a variety of approaches and viewpoints. By sampling the breadth of Aquinas’ reflections on ethical issues and exploring some of the significant connections that tie his moral thought to other parts of his philosophical and theological system, they display the richness and depth of Aquinas’ moral thinking.