Kim du Toit links to a site that people intrested in self-defense might want to take a gander at. Shooting Holes in Wounding Theories: The Mechanics of Terminal Ballistics
The short short version: The guy is an engineer who goes into bullet wounds and lethal wounds with great detail. Knowing just how your bullet works is pretty damn important if your life is going to depend on it. It's a long read, so pull it up at home when you have time, or print it out at work when your boss isn't looking and then read it later.