Kin and kinship matter to us. We are social creatures and our kin or relatives are typically high on the list of those most important to us. Kin are those we care for and who care for us. Our family ties provide a sense of where and with whom we belong. Kin matters also impose boundaries on who we relate to and how, including in sexual and other intimate matters. The study of kinship has been a cornerstone of anthropology throughout its history, but kin matters matter beyond the confines of any academic discipline.Kin Matters: Relational Beings in the Fragile Sciences examines three related themes in the philosophy of anthropology concerning kin matters: the nature of relations, incest and its avoidance, and the study of kinship in cultural anthropology. It develops an integrative framework for thinking about kin matters recognizing that that there should be much more fluidity between the cognitive, biological, and social sciences--the fragile sciences--than one typically finds both in those sciences and in philosophical reflection on them. Along the way, Kin Matters offers a novel account of relations, challenges culture-first explanations of incest avoidance, and advocates for a redirection in the study of kinship.Kin Matters begins by reflecting on our standing as relational beings. We are creatures who actively relate to one another and our worlds to build social and other relationships. Much of that activity is biologically and psychologically mediated and so there is a ready-made place for each of the cognitive, biological, and social sciences in understanding ourselves as relational beings. We are also relatives: we have parents and often enough we have siblings and children. Kinship is something that changes over the course of our lives, but it is there literally from start to end. No wonder anthropologists early on made kin and the study of kinship pillars of their discipline. Yet current views of kinship in anthropology express a wariness of appeals to biology and psychology, and cultural anthropology has long pursued a separatist research strategy in kin matters. Kin Matters opens the way for a more integrative alternative.