On July 10, 1941, Poles in the town of Jedwabne together with some number of German functionaries herded nearly 500 Jews into a barn and burnt them alive. In 2000, the sociologist Jan Gross published a book about the subject that, very shortly thereafter, started a huge controversy about Polish participation in the Holocaust. In the furor that followed, many simply took it for granted that Gross’s interpretation of what happened–that radically anti-Semitic Poles murdered the Jews with little prompting from the Germans–was simply correct. But was it? This is the question Marek Jan Chodakiewicz tries to answer in The Massacre in Jedwabne, July 10, 1941: Before, During, After (Columbia University Press; East European Monographs, 2005). After an exhaustive and meticulous investigation of the sources (which are imperfect at best), Chodakiewicz concludes that we don’t and will never know exactly what happened on that horrible July day in Jedwabne, but it was certainly more complicated and mysterious than Gross imagines. Chodakiewicz puts the massacre in its wider context or, perhaps more accurately, contexts. These include: Jedwabne itself, Polish life there, Jewish life there, the interaction between the two communities in the town, the Soviet occupation, the coming of the Germans, German policies toward Poles and Jews, the Polish resistance, Polish anti-Semitism, Polish anti-Communism, and the intersection of the two (“Zydokomuna“). No punches are pulled: Chodakiewicz places much of the blame for the atrocity squarely on the Poles (or, rather, some faction of them) in Jedwabne. But he puts their actions–insofar as we can know them–into a much wider frame and therefore helps us understand why they did what they did.