The iron marshal - Louis L'Amour

He was a tough enforcer for a New York gang. But when young Tom Shanaghy made one
too many enemies, he skipped town on a fast-moving freight. He landed in a small
Kansas town that had big dreams, no name, and the need for an honest lawman. Tom
figured that a knuckle-and-skull man from Five Points would be perfect for the job.
He didn't know that a high-stakes cattle drive was headed his way and that leading
it was a vindictive rancher bent on settling an old score, even if he had to destroy
the town to do it. Tom had himself stuck in the middle of the feud before sunset
on his first day in town. All he could do was hope that his years on the Bowery had
left him with the smarts he needed to keep himself alive.