Europe in the sixteenth and seventeenth centuries saw an extraordinary proliferation of theoretical ideas about the nature and meaning of emotion, and this introduction offers a survey of the sometimes complementary, sometimes contradictory, intellectual and aesthetic traditions that helped shape this debate. It responds to previous work in the field that has focused primarily on medical humoralism and makes a case for a more pluralistic view of emotion in the period. Renaissance literary texts provide compelling evidence that emotions were not a passive phenomenon, acting upon people’s bodies, but an active, imaginative and philosophical process. Characters in early modern texts often express dissatisfaction with a purely medical understanding of emotion, looking instead to other complex systems of knowledge – including religion and philosophy, rhetorical and language theory, and drama and performance – to articulate and reflect upon their emotional experiences. The introduction thus proposes a rereading of emotional texts from this period with a more pluralistic model of affective experience in mind, paying greater attention to how individuals in this period interrogated, cultivated and performed emotional experience in active and often self-defining ways.