The great medieval philosopher Thomas Aquinas (1224/6-1274) was Dominican regent master in theology at the University of Paris, where he presided over a series of academic debates on ethical topics. This volume offers new translations of disputed questions on the nature of virtue. The introduction explains how Aquinas' theory of virtue fits into his conception of ethics as a whole, and clarifies Aquinas's views by explaining the institutional and intellectual context in which the disputed questions were debated.