Max Brand 
The Quest of Lee Garrison 

Lee Garrison, a solitary fence rider in the southwest, is entranced with stories he has read of daring medieval adventures. Then a dying Indian stumbles into his camp, telling of a magnificent wild mustang called Moonshine. Garrison pursues the elusive horse across the plains on a quest of self-discovery. The chase would lead him across thousands of miles of plains, deserts, and rivers, and before his quest had ended, Lee Garrison would learn the meaning of hope and the cost of dreams. And he would be forced to make a terrible, shattering decision – a decision that might destroy him. Highly recommended, especially for those who love the Old Western genre.