This book began by locating contemporary medical understandings of lifestyle within the context of medical explanatory frameworks in general. We argued that explaining health and disease in terms of lifestyle is not a new approach; however, the contemporary medical understandings of lifestyle which are the focus of this book differ from earlier medical (and lay) ideas about behaviours and health. They are a product of a particular place and time, and represent several key aspects of late twentieth-century thinking about the body and health, namely a concern with identifying and controlling risk, the increasing prominence of epidemiological multivariate analysis as a source of legitimate knowledge about the causes of disease, the self as project and a neo-liberal emphasis on personal responsibility for one’s own health.