Avenue of Spies: A True Story of Terror, Espionage and One American Family by Alex Kershaw

As war comes to Paris, an American Doctor, his wife and son have the choice to flee or to stay and protect the American Hoapital and its patients.  Approached by the French Resistance, hey unhesitatingly accept the risk and become a drop location and help ferry many out of Nazi-occupied France, including downed British and American pilots.  Their teenage son takes photographs (even owning a camera was outlawed) to be sent out of the country.  Eventually, all three are arrested by the Gestapo and sent to concentration camps.  Over and over again they are given opportunities to flee due to their citizenship but chose to stay with those weaker than themselves.  This is an amazing story of personal sacrifice.  I highly recommend.