On Combat: The Psychology and Physiology of Deadly Conflict in War and in Peace - By by Lt. Col. Dave Christensen Grossman, Loren W. Christensen.
I'm not sure if I could even begin to describe how absolutely astounding this book is thus far. I'll just post the amazon link which has a fairly decent description. Is it a military read? Sure it is, but it also encompasses perspectives of all those (from police on the beat to highly trained martial artists who fight for a living) who's job places them in a situations where deadly conflict is either commonplace and/or should be an expected outcome of their daily lives.