Lou Costello was an American comedian born on March 6, 1906. He is best known for his comedic partnership with Bud Abbott in the duo Abbott and Costello. Their hilarious routines, including the famous "Who's on First?" sketch, made them one of the most popular comedy acts in the 1940s and 1950s. Costello's physical comedy and timing endeared him to audiences, and he appeared in numerous films and television shows throughout his career. Lou Costello passed away on March 3, 1959, but his legacy in comedy continues to be celebrated.