Cooper's 'Principles of Personal Defense'
This was recomended in an article by Massad Ayoob; I'd never seen it and just bought and read it. Short and VERY to-the-point.
If you haven't read it, do.
An EDC S&W M&P .45ACP. A dozen Glocks sold. NRA life member.
"If lethal force is warranted and appropriate under the circumstances, the" (defender) "must shoot until the threat ceases." Pinizzotto, Kern, and Davis, FBI Academy.