Beginning with the wildly unsuccessful first performance of Francis Beaumont’s The Knight of the Burning Pestle in 1607, the introduction interrogates the idea of mirth in early modern England. It argues that ‘mirth’ was understood in three distinct but related senses: as a historically inflected hangover from the pre-Reformation past (‘the merry world’); as secular pastime; and as a generic category denoting certain kinds of entertainment. It sets out the emergence of nostalgia for the pre-Reformation past alongside the growth of a competitive professional theatre and print market. The Knight of the Burning Pestle dramatises the dynamic between the nostalgic desire of audience for past pleasures, both theatrical and historical, and the pressure of the competitive theatre towards novelty. The second half of the chapter situates this tension in relation to the historical rupture of the Reformation; to the explosion in cheap print; and contemporary cultures of performance.