"Who's on First?" is a classic comedy routine by the American duo Abbott and Costello. The sketch humorously revolves around a baseball team whose players have unusual names that sound like questions or statements, causing confusion. The first baseman's name is literally "Who," which leads to the famous line "Who's on first?" The routine plays on this wordplay, where "Who" is the name of the player on first base, "What" is on second base, and "I Don't Know" is on third base
. The sketch was first performed nationally on radio in 1938 and became one of the most famous comedy routines of all time. It has been performed in various formats, including film and television, and is recognized as a cultural touchstone in comedy
