Paul G. Markel has published a brief work on how the mind operates before, during, and after an armed lethal-force event. A combat-decorated Marine, former police officer, and small-arms tactics teacher with forty years of using and instructing others in weapons for protecting innocent people, he examines brain regions involved in rapid action and decision-making plus how certain logical principles should shape firearms training.

The text is meant to inform lesson plans and study of the fighting use of guns. It is sold on Amazon as a paperback, Kindle edition, and audiobook.