Health is a concept with many facets or dimensions. To a doctor it typically indicates an absence of signs and symptoms of disease. This overlaps with but by no means exhausts lay understandings. Acknowledging this, sociologists have conventionally distinguished between medical definitions of disease and lay interpretations of illness. Thus, it is possible for people to have a disease without defining themselves as ill, and conversely, for people to define themselves as ill without having a disease. We tend in fact to see ourselves as ill if our lives are disrupted in some way, either through troublesome symptoms that a doctor would recognise, or because through pain or impairment we cannot get on with our lives by going to work or by engaging in normal daily routines. For some, often those enjoying a degree of middle- class affluence and security, the criteria for good health are more ambitious, culminating in a wish for a positive sense of wellbeing. But health need not be confined to the properties of individuals. Populations and even societies are sometimes defined as healthy or otherwise.

The idea of a healthy population or society implies that it is somehow health- bestowing; and that it is inherently comparative, that is, healthy compared to other populations or societies. The criteria used in such cases vary widely, often encompassing data on life expectancy at birth, age- group mortality, health- related quality of life and access to health care services. Many of these measures treat populations, and even societies, as aggregates of individuals. Without denying the usefulness of studies that compare populations and societies in this way, it is a basic tenet of this book that societies and the social institutions that comprise them cannot be reduced to aggregates of individuals. Social institutions and what I shall term social structures do not admit of analysis in these limited and limiting terms.

What follows is the product of long- term frustration. There has accumulated a considerable literature on the health of populations around the globe and on the health care systems that serve those populations. While these accounts often include commentaries on the obstacles would- be reformers face in improving things, missing from many of them is an analysis of the role of impediments that have their tap roots in deep and abiding social structures.