Find the special offer on Abbott & Costello: The Complete Pictures Collection. William Abbott and Lou Costello were an American comedy duo whose work in vaudeville and on stage, radio, film and television made them the most popular comedy team during the 1940s and early 1950s. Their patter routine “Who’s on First?” is considered one of the greatest comedy routines of all time and set the framework for many of their best-known comedy bits. The two men first worked together in 1935 at the Eltinge Burlesque Theater.