I have it and it is definitely worth reading. Has been quite a while since I read it, but the thing that struck me as making it different from most other books that cover the same topics is that Col. Askins had been in numerous gunfights, and had (at least once) permanently turned out the lights of his adversary (be sure and read chapter XXI The Border Patrol). Most historians don't have that in their resume. Askins' accounts of otherwise familiar historical events reflect his "been there, done that" familiarity with life threatening situations, and, from my perspective, add something to the subject matter. The book has chapters on:
The Long Horn Trail
Indian Fights
Hunting Victorio
The Fight at Adobe Walls
The Last Indian Fight
McNellys Rangers
McNelly Rides into Mexico
Outlaws of the Brush Country
Ben Thompson and King Fisher
Lee Hall and John Armstrong
John Wesley Hardin, Texas Badman
Dallas Stoudenmire, Marshal of El Paso
The Buffalo Runners
Sam Bass, the Merry Outlaw
Frontier Skirmishes
Gunfire on the Salt Flats
John Hughes, a Straight Shooter
The Long Ride
Busted Fences
Bandit Troubles
The Border Patrol
Bonnie and Clyde
sjc1, Col. Askins also wrote Gunfighters, another good read.