The Spirit Level: Why Equality is Better for Everyone
The Spirit Level by Richard Wilkinson and Kate Pickett, a book published in hardback by Penguin in March 2009 and paperback in February 2010. An updated paperback version was published in November 2010. The Spirit Level won the 2010 Bristol Festival of Ideas Prize and the 2011 Political Studies Association Publication of the Year Award.
The Spirit Level is available from many independent booksellers and public libraries.
International editions of The Spirit Level
There is currently no French language edition, but you can read some of the evidence in translation.