SummaryThis introductory article sketches out the evolution of the concept of sociability in moral and political debates from Grotius to the German Romantics, so as to elucidate the range and scope of the contributions to this special issue. The article argues that the concept of sociability serves as a bridge between moral theory, domestic politics and international relations, just as it also connects the jurisprudential mode of enquiry to subsequent Enlightenment enquiries into political economy, aesthetics, individual and collective moral psychology, forms of government and philosophical history. Particular attention is paid to sociability's relationship to moral scepticism, and to its position between morality and anthropology. The article highlights the central role of Rousseau in radically reformulating the debate and in sparking new controversies up to the nineteenth century.