After the German and Soviet attack on Poland in 1939, vast swathes of Polish territory, including Warsaw and Krakow, fell under Nazi occupation in an administration which became known as the 'General Government'. The region was not directly incorporated into the Reich but was ruled by a German regime, headed by the brutal and corrupt Governor General Hans Frank. This was indeed the dark heart of Hitler's empire. As the principal 'racial laboratory' of the Third Reich, it was the site of Aktion Reinhard, the largest killing operation of the Holocaust, and of a campaign of terror and ethnic...