Clarence E. Mulford was the author of Hopalong Cassidy, with his other stories and 28 novels followed by radio, feature film, television, and comic book versions. While many of his stories depicted Cassidy and other men of the Bar-20 ranch, he also wrote novels (and short stories) of other Westerners, starting with Johnny Nelson. He also wrote nonfiction, mostly about the West, the outdoors, and motoring.