Detective fiction in general originated with Edgar Allan Poe's short stories set in Paris and featuring C. Auguste Dupin, the first of which was "The Murders in the Rue Morgue" in 1841. The hard-boiled detective story, more specifically, originated with Carroll John Daly's "Three-Gun Terry" in 1923 (although Daly published hard-boiled crime fiction somewhat earlier), and was popularized by Daly and such authors as Dashiell Hammett, Raymond Chandler, Mickey Spillane, and Ross MacDonald (Kenneth Millar).

In fact, Potshot shares some important characteristics with Hammett's Red Harvest (serialized in the pulp detective magazine Black Mask in 1927). In both cases, a private detective is sent to a relatively small western town to defeat a large gang of outlaws.

A similar plot drives the 1960 film "The Magnificent Seven," which is closely related to the 1954 Kurosawa film "The Seven Samuri." Parker makes several obvious references to the former in Potshot, and Chollo...