The classics are "Kill or Be Killed", by Rex Applegate (based on WWII OSS training, a more military orientation, LOOKS dated, but truth never change.
and,
the aforementioned "No Second Place Winner", by Bill Jordan. Again, LOOKS dated, bt truth never...
I also recommend Andy Stanford's book.
Also, Gabe Suarez, the "Tactical Pistol" (though he believes the .45 is a death ray)
Also, Chuck Taylor's "Combat Handgunnery".
These just scratch the surface, there are MANY more.
Don't try to find the lone guru, he doesn't exist, but keep an open mind and learn from all these guys.
The handgun is a limited tool ,and your toolkit must expand to include a shotgun, and a military-style semi autoloader like AR-15 or AK-47.
(At the low end, I also include a belly gun (SP 101) and a bolt action sniper rifle at the upper end.
Listinf these in sequence you see that each tool is effective at a sr\teadily increasing range.
belly gun
main handgun
shotgun
AR -15
Bolt action scoped rifle.
(Then you will integrate empty hand skills, then common household tools like:
butcher knife
golf club
axe handle
tire iron
Boston Slugger
Machete)
Very important, you have to seperate baseline skills like marksmanship, speed reloads, malfunction clearing, shooting under reduced light, etc, from tactics and scenario training.
Learn the skills, then learn how to apply the skills in a real scenario.
Take your time, get the basics down first.
There are a lot of wannabe's out there, but you will start to see that the top guys pretty much say the same things, (when they aren'y OVEREXAGERATING minor differences!!!)