How can we hold in the same view both cultural or historical constructs and generalities about social existence? Kinship, Law and the Unexpected takes up an issue at the heart of studies of society - the way we use relationships to uncover relationships. Relationality is a phenomenon at once contingent (on certain ways of knowing) and ubiquitous (to social life). The role of relations in western (Euro-American) knowledge practices, from the scientific revolution onwards, raises a question about the extent to which Euro-American kinship is the kinship of a knowledge-based society. The argument takes the reader through current issues in biotechnology, new family formations and legal interventions, and intellectual property debates, to matters of personhood and ownership afforded by material from Melanesia and elsewhere. If we are often surprised by what our relatives do, we may also be surprised by what relations tells us about the world we live in.