Shake Hands with the Devil: The Failure of Humanity in Rwanda by Lt.-Gen (Ret.) The Honourable Roméo Dallaire.
Dallaire's experiences in Rwanda left him with PTSD culminating in a suicide attempt in 2000. Reading the book, you can completely understand how he came to be in such a fragile state of mind that he believed suicide was the only way out. It is an incredibly moving and honest look at what occurred leading up to April 6th, 1994, the failings of the international community at large, and the 100 days of bloodshed that followed.
I purchased the book while waiting for a bus one day. My bus stop was in front of Chapters and the rain was coming down in buckets so I headed inside to stay somewhat dry. Shake Hands with the Devil was displayed prominently as I walked in the door. When I went to purchase it the girl behind the counter told me that once I was done the book, I should watch the documentary of the same name. It's as if I knew what a profound experience that book would have on my life because I remember the most insignificant details of that purchase. As hard as it was to read the book, I'm so glad that I did. It made me a better citizen of the world.
I had the privilege of hearing Dallaire speak when he was in Victoria in 2006. He encouraged people who wanted to get involved to volunteer with an NGO. Inspired by him and his words, I put my life in Canada on hold and did exactly that in 2007. I have never, for one second, regretted that decision.