The book opens by discussing the importance of emotion in eighteenth-century theatre in Britain; plays endorsed it, actors performed it, and audiences came to the theatre prepared to experience it. It argues that because audiences judged a play and theatre in general in terms of the emotion it excited, the drama of this period should not be considered as a genre but rather as a mode. Formalist approaches are inadequate and have resulted in a false denigration of later eighteenth-century theatre at a time when moralists and critics praised it as a source of virtue because it enhanced fellow-feeling. Raymond Williams’s concept of‘structures of feeling ‘ provides a means of approaching the theatre of the later eighteenth century as affect rather than form because it focuses on experience, just as eighteenth-century theatregoers focused on their experience of feeling. The introduction concludes with a definition of common eighteenth-century terms such as‘sentiment ‘ and‘sensibility ‘ and their application to theatrical performance.