How Could This Happen: Explaining the Holocaust by Dan McMillan (New York: Basic Books, 2014. 288 pp. $27.99 ISBN 978-0-465-08024-3).

Eighty-two years after Hitler became Reich Chancellor of Germany, seventy-seven years after Kristallnacht, seventy years after the liberation of Auschwitz: time makes no difference. The Holocaust remains an inexplicable phenomenon, the catastrophe of catastrophes, an omnipresent stain on the soul of humanity. In his thoughtful book, Dan McMillan attempts, with remarkable success, to demystify the Shoah, to explain how it happened and why. In doing so, McMillan is well aware of the pitfalls: to explain means to understand; to understand, to render the incomprehensible comprehensible, is to challenge the special status of the Holocaust as unique. McMillan goes to great pains, then, to make distinctions, to inform the general reader why the Holocaust can be explained and yet still maintain its uniqueness. In Chapter 2, “A Genocide like No Other,” he lays out the differences. Rightly acknowledging that comparisons are gratuitous when addressing the suffering of the victims, he nonetheless asserts that it is possible to distinguish motives and governing ideologies–and thus to understand what happened. To that end, McMillan writes that the Holocaust “constitute[s] history’s most uncompromising assault upon the principle that every human being deserves to live” (18). Other genocides, he argues, were perpetrated for “some concrete purpose: for political power, out of perceived military necessity, to seize land and riches, or to enforce religious conversion. Only during the Holocaust have we come to murder a huge population solely for the sake of killing them” (18). In all other mass murders, McMillan continues, at least some proportion of victims could save themselves. In the Holocaust, no such salvation was possible. In McMillan’s view, the “Nazi’s striving for complete biological extinction of the Jews has no parallel in history” (19), and he explains why the genocidal actions against the Armenians in Turkey and the Tutsi in Rwanda differ not only in magnitude but also intent. The Turks stopped their murderous actions against the Armenians while they still held political power; the Hutu leaders had no plans to murder Tutsis who lived outside of Rwanda’s borders (20). Finally, while it may be difficult to attribute motives to the governments then in power, it is possible to say, as McMillan does, that both the Turkish and the Rwanda governments were threatened by an imminent loss of power, leading them to lash out against and then