Large inequalities of income in a society have often been regarded as divisive and corrosive, and it is common knowledge that in rich societies the poor have shorter lives and suffer more from almost every social problem.
This groundbreaking book, based on thirty years' research, demonstrates that more unequal societies are bad for almost everyone within them - the well-off as well as the poor. The remarkable data the book lays out and the measures it uses are like a spirit level which we can hold up to compare the conditions of different societies.
The differences revealed, even between rich market democracies, are striking. Almost every modern social and environmental problem - ill-health, lack of community life, violence, drugs, obesity, mental illness, long working hours, big prison populations - is more likely to occur in a less equal society.
The book goes to the heart of the apparent contrast between the material success and social failings of many modern societies. "The Spirit Level" does not simply provide a key to diagnosing our ills. It tells us how to shift the balance from self-interested 'consumerism' to a friendlier and more collaborative society.
It shows a way out of the social and environmental problems which beset us and opens up a major new approach to improving the real quality of life, not just for the poor but for everyone.
It is, in its conclusion, an optimistic book, which should revitalise politics and provide a new way of thinking about how we organise human communities.