The contributors to this volume demonstrate the significant role that fiction plays in early modern European culture, not only in a variety of its literary genres, but also in its formation of philosophical ideas, political theories, and the law. The volume explores these uses of fiction in a series of interrelated case studies, ranging from the Italian Renaissance to the French Revolution and examining the work of, among others, Montaigne, Corneille, Descartes, Hobbes, Locke, and Diderot. It asks: Where does fiction live, and thrive? Under what conditions, and to what ends? It suggests that fiction is best understood not as a genre or a discipline but, instead, as a frontier: one that demarcates literary genres and disciplines of knowledge and which, crucially, allows for the circulation of ideas between them.