Haycox is the writer most often credited with raising western fiction up from the pulps into the mainstream; his influence on other writers of western fiction cannot be overestimated. He was a prolific writer, with almost three hundred short stories and more than twenty novels to his credit, and is among the most successful writers of American western fiction. Many of Haycox's stories were published in pulp magazines such as "Western Story" before he wrote stories for "Collier's Magazine" and "The Saturday Evening Post." His final works, "The Earthbreakers" and "The Adventurers," were published after his death.