In the months following Hitler’s invasion of the Soviet Union, SS squads — the so-called Einsatzgruppen — executed hundreds of Muslim prisoners of war who had fought in the Red Army, assuming that their circumcision proved that they were Jewish. In Berlin, these executions soon became the subject of controversy. During a meeting of officers of the Wehrmacht, SS and Ministry for the Occupied Eastern Territories in summer 1941, Erwin von Lahousen, an official of the Wehrmacht intelligence agency representing his boss, Wilhelm Canaris, engaged in a row with the head of the Gestapo, Heinrich Müller, about these killings. Lahousen brought up the selection of hundreds of Muslim Tatars, who had been sent to ‘special treatment’ because they were ta...