The personal papers of one of World War II's earliest historians reveals an obsession with how Nazis distorted the German language.

They did not wait for the war to end.

In August 1944, as soon as Soviet troops swept the Nazis out of eastern Poland, a group of Jewish intellectuals rushed to cities like Lublin and Lodz to begin collecting and recording, scouring for any trace of the still fresh horror that had taken their own loved ones. They wanted evidence.

Among them was Nachman Blumental, a philologist obsessed with the uses and misuses of language. He had escaped into