This chapter looks at definitions of humour, as opposed to wit and comedy, and delineates the fin de siècle New Humour specifically. It shows how New Humour was defined by its critics, and associated with the mass, inconsequentiality, urban vulgarity, and Americanness. It was seen as representing and being consumed by newly literate clerks, cockneys, and the figure of the ‘Arry. It uses the incongruity theory of humour to show its texts as challenging accepted social narratives and norms, and parodying specific adventure narratives, by casting the small things of life as grand, and grand adventures as low. Looking at contemporary and Victorian definition of humour, it uses Henri Bergson’s idea of humour as something mechanical encrusted on the living to show how New Humour defaces its source texts to show the anxieties and potentialities of late-nineteenth-century modernity. It argues that humour’s role is to show the contractedness of society, and to push against it. It unsettles assumptions of purpose, progress, identity, and stability. New Humour is shown to reveal the pretence and mechanicality of life.