I believe Zane Grey's RIDERS is the most often-filmed Western novel of all time. This 1941 version from Fox is a low-budget but fast-moving adventure starring a very young George Montgomery, who manages to look dashing dressed all in black and wearing a very wide-brimmed hat, the likes of which probably were never seen in the Old West. Montgomery plays Lassiter, a loner who comes to the aid of a distressed cattle ranch and finds himself crossing swords with a crooked judge and his gang of cut-throats. Lots of fancy horseback riding, some shooting, and a fistfight or two. Some familiar actors of the period turn up in this oater, including Kane Richmond and Richard Lane. Worth a look for Montgomery, who grew up around horses. The fact that he never became a big star is curious. He actually is best known for having been married to Dinah Shore. I remember him best not from the movies but from an early TV show where he played -- what else? -- a cowboy.