Richard Wilkinson, Kate Pickett.
The Spirit Level: why equality is better for everyone.
Penguin. 2009
Why do we mistrust people more in the UK than the Japanese do?
Why do Americans have higher rates of teenage pregnancy than the French?
What makes the Swedish thinner than the Australians?
The answer: inequality.
Based on years of research, this is the most influential and talked about book on society in the last decade.