Comedy has undergone a seismic shift over the past quarter century: from star powered stand-up comics to an ensemble-fueled style marked by support, trust, and collaborative creativity. This shift is mainly due to the long form improvisational theatre structure known as the Harold. The form's philosophies serve as the bedrock for the majority of the most significant comedic performers, writers, and directors of the past quarter-century who are transforming the way peformers and audiences make, view, and interpret comedy. This book examines the development of the Harold and the ways in which it has helped transform American comedy, examining the tensions and evolutions that led to the Harold's creation at ImprovOlympic (now iO) and following it through its use in contemporary comedic filmmaking.