Their Darkest Hour : People Tested to the Extreme in WWII

Their Darkest Hour - Laurence Rees Rees interviews a number WWII veterans for all sides and asks them about their motivations for contributing to atrocities that were committed during the war. It is a little biased in favour of the modern western mindset however the insights into the (mostly) ordinary people mixed up in WWII makes the book worth reading.