Once considered inimical to ethics, Karl Barth's theology is now rightly recognized for the central role ethics plays in it. But can Barth be safely placed in the mainstream tradition of Christian moral theology or does he offer a challenge to the latter? Gerald McKenny argues that the claim that God not only establishes the good from eternity but also brings it about in time is of fundamental importance to Barth's mature ethics. The good confronts us from the site of its fulfilment in Jesus Christ, who has accomplished it in our place. The result is a vision of the moral life as a human analogy to God's grace, a vision which contrasts with the bourgeois vision of the moral life as an expression of human capability. Barth's moral theology is presented here as the attempt to reorder ethical thought and practice in light of this fundamental claim. This lucid and well-argued study is the most comprehensive treatment of Barth's ethics to date, offering a thorough account of the development of Barth's ethical thought and a wide-ranging analysis of its chief concepts and arguments. McKenny explains why certain widespread assumptions about Barth's moral theology are mistaken and explores the rich, complex, and often surprising ways in which Barth's position engages the traditions of Christian ethics and modern continental moral thought. Above all, McKenny shows why Barth's moral theology deserves our attention in spite of, or rather because of, its uneasy fit in the mainstream tradition of Christian moral theology.