Training involves more than the physical. Sure, we need to spend time practicing our skills, and strengthening and stretching our bodies -- but we also have to exercise and work our mind, too. In no particular order, here are a few books I recommend taking some time with.
Meditations on Violence, Rory Miller.
Rory's walked the walk, and he talks the talk. He retired from working as a corrections officer, where he quite honestly dealt with more criminals day in and day out than most cops do. He also spent some time in a hot, sandy place, as a teacher. It's sometimes unsettling, but definitely worth the read. And re-read. (Oh, and he's got another book soon to come out, titled Facing Violence: Preparing for the Unexpected.)
On Killing, David Grossman.
David Grossman is a retired US Army colonel and psychologist. He's currently a public speaker, focusing on the psychological effects of violence, especially of killing and being exposed to life & death conflicts. His work is based on lots of interviews and discussions with people who've been there... and he openly admits he hasn't. I don't agree totally with everything he says -- but he's got a lot of good points. And, especially for the military and law enforcement, if you get a chance to attend his Bulletproof Mind presentation... go for it. (I suspect the cd/audiotape version is much the same... but I don't think all of his dynamic presence will come through.)
Training at the Speed of Life, Ken Murray.
THE guide to scenario based training for law enforcement and the military. And scenario based training is one of the best ways to prepare yourself for real violence.
Karate-do:My Way of Life, Gichin Funakoshi.
The autobiography of the "founder" of modern karate. Funakoshi is credited with introducing karate to Japan from Okinawa, and shaped lots of how karate and many other martial arts are trained today. There are some good insights for any martial artist in learning about his training and his life.
Unfinished Murder: The capture of a serial rapist, James Neff.
Very interesting insight into the story of a real-life serial rapist in the Cleveland, Ohio area. The author got to spend a lot of time with Ronnie Shelton, and it gives a really powerful insight into what goes into the making of a serial rapist -- especially since it's probably not much more than luck that he never became a serial killer.
For Bando students... Dynamics of Bando by Joe Manley and Lloyd Davis is essential reading. The insights into these giants of our system and their training is invaluable.