The question of how "ordinary Germans" managed to commit genocide is a classic (and troubling) one in modern historiography. It's been well studied and so it's hard to say anything new about it. But Mary Fulbrook has done precisely that in A Small Town Near Auschwitz: Ordinary Nazis and the Holocaust (Oxford University Press, 2012). In the book she examines the career of a single Nazi administrator in "the East", Udo Klusa, in minute detail day by day, week by week, month by month while the Germans were improvising what became known as the "Holocaust." Klausa was not a big wig; he was a functionary, a part of a (particularly awful) colonial machine. He believed in the Nazi mission to "Germanize" Poland, but he was by no means a "fanatical" Nazi. He followed orders (by our standards horrendous ones), but he did not do so mindlessly. He wanted to build a career, but he was not–apparently–willing to do anything to do so. Fullbrook investigates just how far Klausa was willing to go, what he found acceptable and what he found (or seemed to find) objectionable. It's a tricky subject because Klausa himself tried to cover his tracks after the war. He seems to have seen that policies he once found quite sensible were, after the war, not so. Fullbrook does a masterful job of using archival sources to show where Klausa's memory becomes particularly selective. Though it would be too much to call Fullbrook's portrait of Klausa "sympathetic," it is certainly both historically and psychologically nuanced and therefore helps us understand his mentality both during the war and after.