This is a great little piece of history. During WWII the Office of Strategic Service (later to be known as the CIA) sent a guide into occupied territories to help workers sabotage the enemy war effort. What's cool is so many of the lessons in the guide are relevant to how some people work today. Do you like your job?

http://www.bbc.com/capital/story/20171211-the-world-war-two-guide-to-office-warfare

As someone who works on countering insider threats for a living, this was a fascinating read for me.