Like AtlLaw said in the early 70s a lot of officers that wanted to go home at night would read just about anything to do with gun fighting they could get their hands on. Bill Jordan and Jeff Cooper were the two I read.
I found Cooper to be arrogant and one way minded ALL THE TIME, but liked his mind set theory and taught it, and practiced it. In that regard, Cooper was dead on.
Bill Jordon was John Wayne in that he was REALLY OLD SCHOOL. He literally is responsible for Smith and Wesson CREATING the light and fast, Model 19 Combat Magnum (357 mag in a K frame), and in that regard he was truly RIGHT!
Bill Jordan's idea was to stand and fight. You can't hit anything while your running.
A shoot from the hip shooter he was once recorded to have drawn and fired, hitting I believe an aspirin resting on the back of his gun hand in .27 of a second.
He did the same with ping pong balls, putting them on the back of his gun hand, and drawing and hitting the ball with the muzzle before the ball could fall. He was numerous times used by attorneys in court to demonstrate DOING, what someone said COULDN'T BE DONE, with a revolver. I believe he also INVENTED the steel lined JORDAN HOLSTER.
The book is a good read, but may cause one to question the real need for high capacity pistols in a fight.