Joe Heydecker was born of liberal German parents in Nuremberg and had a half-brother whose father was Jewish. A conscript to the German army, with a previous training in photography, he was allocated a post in the Propaganda Training and Replacement Centre in Potsdam, later being sent to Warsaw. It was here, at great personal risk, that he made this historic series of photographs. With the help of his wife he was able to hide the negatives until after the war. No prints from the negatives were made until 1981 when his book Where is Thy Brother Abel? was published.