This book offers a unified collection of published and unpublished papers by Robert Audi, a renowned defender of the rationalist position in ethics. Taken together, the essays present a vigorous, broadly-based argument in moral epistemology and a related account of reasons for action and their bearing on moral justification and moral character. Part I details Audi's compelling moral epistemology while Part II offers a unique vision of ethical concepts and an account of moral explanation, as well as a powerful model of moral realism. Part III extends this account of moral explanation to moral responsibility for both actions and character and to the relation between virtue and the actions that express it. Part IV elaborates a theory of reasons for action that locates them in relation to three of their traditionally major sources: desire, moral judgment, and value. Clear and illuminating, Audi's introduction outlines and interconnects the self-contained but cumulatively arranged essays. It also places them in relation to classical and contemporary literature, and directs readers to large segments of thematically connected material spread throughout the book. Audi ends with a powerfully synthetic final essay.