It is possible to improve the lives of the poor, the middle class and the well off, by addressing one big problem.
It turns out that reducing economic inequality can reduce a whole range of social problems, from teenage pregnancy and youth violence, to heart disease and depression.
The authors of a new book say the world's rich countries have benefited about as much as they can from economic growth. Improvement in the quality of life now hinges on increasing economic equality.
We've long known that poor people have worse health problems, and more recent studies have demonstrated that in more unequal societies even wealthier people suffer health consequences, especially stress-related diseases.
Two British researchers, Richard Wilkinson and Kate Pickett, go beyond health and demonstrate links between inequality and many social problems that ultimately affect everyone.