In his day, theologian Reinhold Niebuhr (1892-1971) was immensely influential - a public intellectual and author of many books who even appeared on the cover of Time magazine (in 1948). He was a realist in political philosophy, and his book The Irony of American History continues to speak directly to the question of American imperialism. The current international situation requires serious reflection of the kind at which Niebuhr excelled, and Niebuhr's thought has experienced something of a revival. Pundits and politicians from James Fallows, Jean Bethke Elshtain, and David Brooks to Bill Moyers, and Senators John Danforth and Barack Obama all cite Niebuhr's work with approval. If Niebuhr is attractive as a tough-minded political realist, he is insufficiently orthodox for some Christian theologians and ethicists. In this book, Richard Crouter offers an accessible introduction to Niebuhr's religious and political thought, while attempting to discover how Niebuhr can appeal to persons belonging to opposing political and religious camps, and whether his uncanny ability to speak to atheists as well as believers is a strength or weakness.