The Messenger

Jan Karski, a young Polish diplomat turned cavalry officer, joined the Polish underground movement after escaping from a Soviet detention camp in 1939. He served as a courier for the underground, ferrying messages between occupied Poland and the exiled Polish leaders, before he was captured and brutally tortured by the Gestapo. 
Escaping from the Germans, Jan Karski was charged with the mission of his lifetime: to convey a message to the Allies about Hitler's program to exterminate the Jews of Europe. He visited Warsaw's Jewish Ghetto so that he could relate the truth about inhuman conditions first hand when he met, soon after, with leaders and top officials in London and President Roosevelt in Washington.  
He had the ears of the decision-makers, yet nothing was done to prevent the ultimate fate of millions of Jews. 
Published to immense acclaim in France, under the title Jan Karski, The Messenger is a compelling and tragic story. An extraordinary novelised biography about a man's moral courage and our collective humanity, with parallels to Thomas Keneally's Schindler's Ark and WG Sebald's Austerliz.