The 20th century has seen impressive gains in health and life expectancy in many parts of the world – but these improvements are unequally distributed. In every country, poor people and those from socially disadvantaged groups get sicker and die sooner than people in more privileged social positions. Not only is there a gap in health between the best-off and the worst-off in society, there is a gradient in health running between them. This gradient can be linked clearly to social and economic conditions. The Commission on Social Determinants of Health was set up by the World Health...