In this article I offer an overture to social life, starting from the premise that every living being should be envisaged not as a blob but as a bundle of lines. I show that in joining with one another, these lines comprise a meshwork, in which every node is a knot. And in answering to one another, lifelines co-respond. I propose the term ‘correspondence’ to connote their affiliation, and go on to show that correspondence rests on three essential principles: of habit (rather than volition), ‘agencing’ (rather than agency), and attentionality (rather than intentionality). I explain habit as ‘doing undergoing’, agencing as a process in which the ‘I’ emerges as a question, and attention as a resonant coupling of concurrent movements. I discuss the ethical and imaginative dimensions of correspondence under the respective rubrics of care and longing. Finally, I spell out the implications of a theory of correspondence for the way we approach classic themes of anthropological inquiry, including kinship and affinity, ecology and economy, ritual and religion, and politics and law. In a coda, I suggest that anthropology, too, must be a discipline of correspondence.