Witness to an Extreme Century, by Robert Jay Lifton
Near the end of his memoir, Robert Lifton writes about Victor T., a Jewish doctor who had been an inmate at Auschwitz. While at Auschwitz he acted heroically, tending to patients in one of the camp's infirmaries and often endangering his own life in order to save theirs. Yet when Lifton went to interview Dr. T in the late 1970s, he found that he was haunted by his actions at Auschwitz, critical of himself for perceived failures and for things that he did in order to survive.