some key points

What does the book talk about?
Method:
they use the information to create a series of scatter-graphs whose patterns look nearly identical, yet which document the prevalence of a vast range of social ills. On almost every index of quality of life, or wellness, or deprivation, there is a gradient showing a strong correlation between a country's level of economic inequality and its social outcomes. Almost always, Japan and the Scandinavian countries are at the favourable "low" end, and almost always, the UK, the US and Portugal are at the unfavourable "high" end, with Canada, Australasia and continental European countries in between. (2)
（2011年五月份写的notes啦，当时为了课上的debate而写的一点儿notes，写过的summary却找不到了。）
As the authors write, "the relationships between inequality and poor health and social problems are too strong to be attributable to chance".
Assumption:
In its most simple terms, the book yearns for society to celebrate humankind's ability to co-operate and support one another.　（1）we are not fighters, but lovers.
The authors argue that removal of economic impediments to feeling valued - such as low wages, low benefits and low public spending on education, for instance - will allow a flourishing of human potential. (2)
They can only do better when they feel valued
Evidence: (evidence-based policy)
Argument: any increase in inequality means more crime, poorer education, more disease and violence (?)
Causal Claim Chain:
Statistic data from 23 rich countries and 50 US states-> conclusion drawn from those sample: more unequal, more social and health problems->‘A key explanation is the psychological impact of inequality which, they say, causes stress and anxiety’.
Limits role of economy
Propose economy equality
Crucially, the authors argue that the evidence shows that all levels of society benefit from more equality, not just the poorest. On health, "at almost any level of income, it's better to live in a more equal place". Whether rich or poor, inequality causes stress, which causes biological reactions that put pressure on the body and increase illness. (1)

Conclusion:
Arguably the most profound conclusion is that economic growth among rich countries has finished its work because it is no longer increasing life expectancy and the only way to do that is to better share the wealth we have (1)
Bigger society, bigger government-‘For a book which concludes that either taxes must rise on the rich (Nordic model) or their incomes must fall to increase equality (Japan Model), it was an astonishing level of cross-party support.’ (1)

Ambition:
Transcend party politics, and make Britain a happier, less-divided, more sociable, healthier and safer place
Acclaim:
Data source are reputable and authoritative

Criticism:
From the rightwing, ‘unpalatable’ (1)
In fact, the success of cut programme so important to the government’s credibility (1)
does not believe that The Spirit Level's claim that the psychological effects on society of income inequality are so great to cause widespread social ills. "I don't think people outside the intelligensia worry about inequality," Snowdon said. "The working class don't worry about how much Wayne Rooney is earning." (1)
The attacks challenge the Spirit Level's interpretation and selection of statistics in concluding the causal link between inequality and social ills and dispute Wilkinson and Pickett's dismissal of other factors, including race and culture, as possible explanations for the relationship. (1)
Is equality a political will ? (2)
Japan has much less population than us., smaller geography
Effects in Political Debate:
This book ignites the unjustified inequality out of the moral and ethics debate into social and political stage.