Introduction: Niebuhr's enduring relevance -- Contextualizing Niebuhr : a biography and a sketch of his intellectual development -- Niebuhr on human nature -- Niebuhr on collective society, nations and international relations -- Niebuhr on the UN, globalization, and the potential for national transcendence -- Niebuhr on U.S. policy in the Cold War -- Niebuhrian take-aways on the just war tradition and the US invasion of Iraq -- Niebuhrian take-aways on humanitarian intervention and the responsibility to protect -- Niebuhrian take-aways for the West regarding the twenty-first century rise of China -- Locating Reinhold Niebuhr in contemporary IR theory