I have been involved with martial arts for over 25 years. I have military experience and retail loss prevention experience. I say this because I want you to know from where I am coming.
I just finished an excellent book last night by Rory Miller. "Meditations on Violence" is refreshing because of what it is NOT. It is not a book filled with techniques:"If the attacker does THIS, then you do THAT." There is a place for that kind of text, and there are hundreds (thousands?!) of that type.
Instead, "Meditations On Violence" delves into both the intellectual and practical aspects of violence, use of force, and implications for training.
I highly recommend it!