High Quality Content by WIKIPEDIA articles! William "Bud" Abbott and Lou Costello (born Louis Francis Cristillo), 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 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.