"The Common Law Origins of the Infield Fly Rule" is the title of an article by William S. Stevens published in 1975 in the University of Pennsylvania Law Review. The brief eight-page article has vastly surpassed its modest original context, having been cited in federal and state judicial opinions and more than 100 works of legal literature. It has been included in a number of anthologies of baseball law, and prompted copycat and parody articles. The New York Times called the article "one of the most celebrated and imitated analyses in American legal history."

Baseball law refers to the various civil statutes, local ordinances, and court decisions pertaining to the game of baseball and its institutions, as distinguished from the Rules of Baseball, which are a private codification of rules governing the internal workings of baseball games.