While huge teams of men were laying track across the Great Plains, the area was not completely empty. It was full of huge ranches, millions of cows, and those hardworking hombres in the saddle—cowboys.

The cowboy is one of the most romantic figures of the Old West. But his popular image does not often square with reality. Real cowboys were poorly paid laborers. They rode endless miles in the snow, wind, and rain. In the summer, the scorching prairie sun beat down on their brains. Most of their time was spent fixing fences and chasing down lost calves. Some men actually did bust broncos, shoot it out with Indians, and lasso bears, but these feats were not common to the life of the average wrangler. Yet tales of rare and reckless deeds helped enshrine the cowboys as the heroes of some of...