Find out who's on first with Abbott & Costello. They are one of the greatest comedy teams in the history of show business.

William (Bud) Abbott and Lou Costello (born Louis Francis Cristillo) performed together as Abbott and Costello, an American comedy duo whose work in radio, film and television made them the most popular comedy team during the 1940s and 50s. Thanks to the endurance of their most popular and influential routine, "Who's on First?"—whose rapid-fire word play and comprehension confusion set the preponderant framework for most of their best-known routines—the team is, as a result, featured in the Baseball Hall of Fame. (Contrary to popular belief, however, the duo was not inducted into the Hall.)

Radio
After working as Allen's summer replacement, Abbott and Costello joined Edgar Bergen and Charlie McCarthy on The Chase and Sanborn Hour in 1941, while two of their films (Buck Privates and Hold That Ghost) were adapted for Lux Radio Theater. They launched their own weekly show October 8, 1942, sponsored by Camel cigarettes.

The Abbott and Costello Show mixed comedy with musical interludes (by vocalists such as Connie Haines, Ashley Eustis, the Delta Rhythm Boys, Skinnay Ennis, and the Les Baxter Singers). Regulars and semi-regulars on the show included Artie Auerbach ("Mr. Kitzel"), Elvia Allman, Iris Adrian, Mel Blanc, Wally Brown, Sharon Douglas, Verna Felton, Sidney Fields, Frank Nelson, Martha Wentworth, and Benay Venuta. Ken Niles was the show's longtime announcer, doubling as an exasperated foil to Abbott and Costello's mishaps (and often fuming in character as Costello routinely insulted his on-air wife). Niles was succeeded by Michael Roy, with announcing chores also handled over the years by Frank Bingman and Jim Doyle. The show went through several orchestras during its radio life, including those of Ennis, Charles Hoff, Matty Matlock, Jack Meakin, Will Osborne, Freddie Rich, Leith Stevens, and Peter van Steeden. The show's writers included Howard Harris, Hal Fimberg, Parke Levy, Don Prindle, Eddie Cherkose (later known as Eddie Maxwell), Leonard Stern, Martin Ragaway, Paul Conlan, and Eddie Forman, as well as producer Martin Gosch. Sound effects were handled primarily by Floyd Caton.

In 1947 Abbott and Costello moved the show to ABC (the former NBC Blue Network). During their time on ABC, the duo also hosted a 30-minute children's radio program (The Abbott and Costello Children's Show), which aired Saturday mornings, featuring child vocalist Anna Mae Slaughter and child announcer Johnny McGovern.