Edwin Black's book about how IBM helped automate the Nazi death machine in Poland is stunning, even though most people who think about the European genocide of the 1940s won't be surprised by the overall fact of it. It being - to say it plainly again - IBM's connection to the Nazi final solution. It was a strategic business alliance. Perhaps more frighteningly, it was the dawn of the era - ours - in which what we now call "information technology" tended to help destroyers and mass murderers more than advocates of democratic values. It's all about the real dangers of human taxonomies - identifying a person in a fixed (1's and 0's) sort of way.
Here's a link to a summary article Black himself wrote for the Village Voice in 2002, around the time his book was published. And here's a link to Black's home page. The book is called IBM and the Holocaust.