This volume presents Habermas's most recent contributions to ethical theory, expanding and clarifying his controversial theory of discourse ethics. Responding to criticisms of his theory, Habermas defends the claim of discourse ethics to a central position in contemporary moral philosophy. He explains and refines the key concepts of his approach and extends the argument in certain key respects, including his treatment of practical reason and of the problems of application and motivation. The first chapter offers a comprehensive analysis of practical rationality which establishes a clear demarcation between pragmatic, ethical and moral questions and a corresponding differentiation between forms of volition and spheres of practical discourse. Habermas then develops a wide-ranging defence of discourse ethics and provides a masterly critique of the major competing positions, such as those of John Rawls, Bernard Williams, Charles Taylor, Alasdair MacIntyre, Karl-Otto Apel and Albrecht Wellmer. The remaining chapters defend the basic intention of universalist moral theory in the face of the claims of the neo-Aristotelian ethic of the good and of Horkheimer's scepticism towards reason. An interview with Habermas, covering such topics as the genesis of discourse ethics, the precise import of some of its more controversial elements and its interconnections with the theory of communicative action, concludes the volume. Justification and Application engages with some of the most important and controversial issues in social and political theory and philosophy today. It will be welcomed by students and scholars throughout the social sciences and humanities.