Reinhold Niebuhr (1892-1971) was a major American theologian and political thinker of the mid-twentieth century. He has received much attention from biographers and historians in recent years, but, since his thought remains very relevant for contemporary ethics, a reassessment is due of what he might contribute to current thinking about politics and society. This book is intended to present Niebuhr's ideas about "Christian Realism" in a way that will be useful to people who are thinking about today's social issues.