The twentieth century bears the indelible imprint of both communism and Nazism. Today, it sometimes seems as if the former is all but forgotten, at least among Western elites, while our cultural memory of the latter is an inextinguishable fire. This inequality is surprising and calls out for explanation, a task the French political thinker Alain Besancon attempts here in a wise and elegant meditation. In examining the horror and destruction caused by both of these terrible ideologies, Besancon finds that recourse to theology is necessary if we are to achieve even feeble illumination. He also explains why, even with the full knowledge of the extent of communism's crimes, the uniqueness of the Shoah ought to be accepted without reservation.