Max Brand 
On the Trail of Four 

When Hugo Ames found Truck Janvers dying from gun wounds in his mountain shack all the old miner had time to say was, “My boy—San Marin—” before a knife, hurtled out of the darkness, silenced him forever. By morning Ames had found the tracks of the four men who’d brought Truck down to die without giving him a fighting chance.

Even though Ames was an outlaw with a price on his head, he’d never harmed a defenseless man, and he couldn’t stomach men who did. So he left the safety of the hills to track down the cold-blooded killers—and rode straight into the greatest danger of his life!