Looking at human sickness and healing through the lens of evolutionary theory, this work presents not only the vulnerability to disease and injury but also the need to show and communicate sickness and to seek and provide healing as innate biological traits grounded in evolution. This linking of sickness and healing, as inseparable facets of a unique human adaptation developed during the evolution of the hominid line, offers a point from which to examine medicine. The author traces the characteristics of sickness and healing through the early and later stages of social evolution. As well as offering a conceptual structure and a methodology for analyzing medicine in revolutionary terms, he shows the relevance of this approach and its implications for the social sciences and for medical policy.