"Who's on First?" is a famous comedy routine popularized in 1933 by American comedy duo Abbott and Costello. Known for its clever wordplay and humor, the sketch involves a conversation about baseball players with confusing names, leading to a series of comedic misunderstandings. This routine exemplifies early 20th-century entertainment and highlights Abbott and Costello's exceptional comedic timing. Its enduring influence has cemented it as a classic example of American humor and a significant cultural artifact.