This monograph, which is based on two years of field research carried out in collaboration with medical doctors, explores Yupno conceptions of the link between personal illness and disturbed social relations. Using the sickness and treatment of a small child as a central narrative device, Keck shows how the Yupno chart the onset and course of sickness in relation to imbalances in bodily humours caused by disturbed, burdened social relations. She also compares Yupno ways of diagnosing and treating illness with those of biomedicine—in particular, as these were in evidence in the treatment of the sick child—in order to underscore their specificity, and to show how they link to local conceptions of personhood, emotions, and social equilibrium. This book will be of interest for all scholars working in the field of medical anthropology, and for a general readership interested in Melanesia and the Pacific.