John Rambo, Harry Bosch, Elvis Cole's partner Joe Pike and other veterans of the Vietnam War era — who have served hard-boiled fiction so well over the past three decades — are getting too old for the sort of mayhem their authors would have them perform.
Enter Lee Child's series character, Jack Reacher. A West Point graduate and former military cop, he served in the 1991 Persian Gulf War. Standing 195 cm tall, he's a seasoned brawler, and while adept at firearms, he typically overcomes multiple assailants through brute physical strength and sheer meanness.
Reacher's ongoing saga is somewhat reminiscent of the 1960s TV ronin Kogarashi Monjiro, a nihilistic anti-hero whose characteristic catchphrase was, "It's nothing to do with me." After becoming fed up with the army after 13 years service, Reacher became an aimless vagabond possessing little more than the clothes on his back and a folding toothbrush in his pocket.