Challenging Rational Explanations of Genocidal Killing and Altruism Review of HITLER'S WILLING EXECUTIONERS: ORDINARY GERMANS and the HOLOCAUST, by Daniel Jonah Goldhagen; REVOLUTION and GENOCIDE: ON the ORIGINS of the ARMENIAN GENOCIDE and THE HOLOCAUST, by Robert Melson; the HEART of ALTRUISM: PERCEPTIONS of a COMMON HUMANITY, by Kristen Renwick Monroe; RAOUL WALLENBERG, by Harvey Rosenfeld