Reinhold Niebuhr could not think thoroughly about the Holocaust. This may surprise some, for Niebuhr is generally known as the hard-headed realist who understood sin and evil to be real and active in the world. Niebuhr could not think thoroughly about the Holocaust because he could not think thoroughly about the emergence of a new type of evil. If Germans took pleasure in the destruction of Jews for its own sake, then the meaning of history is itself put at risk, at least for those who would learn from Niebuhr. For all his realism about sin and evil, Niebuhr cannot imagine a world in which the mysterious meaning of history will not be revealed at the end of days. For many who survived the Holocau··st, Auschwitz was the end of days. This does not make their experience definitive for the rest of us. It does mean that evil, when pursued for ends that are fundamentally meaningless, threatens both faith and confidence in the meaning of history. In thinking about the Holocaust, this essay draws not only on Hannah Arendt, but also on my own research in the Fortunoff Video Archive for Holocaust Testimony at Yale University.