Americans now learn about the Holocaust in high school, watch films about it on television, and visit museums dedicated to preserving its memory. But for the first two decades following the end of World War II, discussion of the destruction of European Jewry was largely absent from American culture and the tragedy of the Holocaust was generally seen as irrelevant to non-Jewish Americans.

Today, the Holocaust is widely recognized as a universal moral touchstone. In Reluctant Witnesses, sociologist Arlene Stein--herself the daughter of a Holocaust survivor--mixes memoir, history,...