A few years ago I read The Nazi Doctors by Robert Jay Lifton. If you're interested at all in the way that humans can commit atrocities against other humans, I highly recommend it. Despite being a very thick book, it is very engrossing.

During my research for a stats paper I'm supposed to be writing, I came across this.
It backs up a lot of Lifton's ideas, as to the rise of Nazi-style thought and action being reproducible at any time in human history if the infrastructure and public opinion is right... In other words, the Nazis were not merely a random group of psychopaths, but what they were was woven into the fabric of their society.