It’s available from Oxford University Press, Amazon, and elsewhere. The introductory chapter is online here. From the opening:

Historically, the belief that inequality is unfair was the main reason for objection to it. In recent decades the source of opposition has shifted. A prominent concern now, perhaps the dominant one, is that inequality may have harmful effects on a range of outcomes we value, from democracy to opportunity to health and more.

The case for inequality reduction surely is much stronger if this is true. Is it true?

I examine the country evidence on the effect of income inequality on living standards, democracy, equality of opportunity, longevity, and happiness. As it turns out, support for the notion that reducing inequality will improve other outcomes is underwhelming.

Rich democratic nations with higher levels of income inequality or larger increases in income inequality haven’t tended to have slower economic growth, lower or slower-growing household income, or worse household balance sheets.

Government policy decisions tend to reflect the preferences of people with high incomes more than those of people with middle or low incomes. That’s inconsistent with what we’d like in a democracy — equal opportunity for political influence. However, in the United States, which has experienced a large rise in income inequality since the late 1970s, the amount of inequality in political influence hasn’t increased. Nor does it appear to differ notably from other nations that have far lower levels of income inequality. So even if the United States was able to reduce income inequality back to the level of the late 1970s, its lowest level ever, there is little reason to expect that would reduce inequality of political influence.

There are a number of pathways through which income inequality might increase inequality of opportunity, from family structure to family expenditures to schools and neighborhoods. Yet evidence that reducing income inequality will significantly reduce inequality of opportunity is quite thin.

The notion that income inequality is harmful for health has received substantial attention from researchers, and some now take it for granted that inequality reduces longevity. But the country evidence offers very little support for this conclusion.

Does income inequality and its rise account for why the rich democratic nations have had so little improvement in life satisfaction since the 1970s despite rising incomes and living standards? Inequality might be a contributor, but if so it appears to be a minor one.

None of this tells us that inequality isn’t a problem. But it does strongly suggest that inequality isn’t the problem. Reducing income inequality isn’t likely to significantly boost living standards for the poor or the middle class. It probably won’t do much to equalize political influence. It’s unlikely to help much with equalization of economic opportunity. It probably won’t make much difference for our health. And it’s doubtful that it will facilitate a rise in happiness.

We have less data with which to assess the consequences of wealth inequality. But two key facts from the country experience recommend skepticism about the wealth-inequality-is-harmful hypothesis. One is the success of the Nordic countries in creating good outcomes despite comparatively high wealth inequality. The other is the massive advance in wellbeing in France over the past two centuries despite the small and stagnant wealth share held by the bottom half of the French population.

We’re likely to make more progress in living standards, democracy, opportunity, health, and happiness by pursuing these outcomes directly, rather than by hoping to achieve them indirectly via a reduction in income inequality or wealth inequality.

Much of the gap in income and wealth between people is undeserved, because most of what determines where each of us ends up on the socioeconomic ladder is beyond our control. Less economic inequality would be fairer. Moreover, lots of people would like there to be less inequality. Reducing inequality of income and wealth is therefore a sensible goal. I’ll offer suggestions for how to do this.

At the same time, inequality reduction shouldn’t be a top-level priority. We don’t need the Gini coefficient or the top 1 percent’s income share to be among our headline economic and social indicators. We don’t need to enact a policy whereby tax rates shift automatically in order to hold income inequality at a constant level. I don’t think we should impose a cap on the amount of income or wealth a person can have. It wouldn’t be wise to decrease spending on government services in order to fund a universal basic income, even though doing so would sharply reduce income inequality. And while widespread homeownership is an effective way to reduce wealth inequality, we should hesitate to encourage that.

Our principal aim should be to make people’s lives better, especially by bringing up the floor of living standards and wellbeing. A key element of this is public goods and services. These don’t show up in measures of income or wealth, so they don’t contribute to reduction of income inequality or wealth inequality. But they matter greatly for our capabilities and quality of life.

Chapter list:

1. Inequality Isn’t the Problem
2. Is Income Inequality Bad for Living Standards?
3. Does Income Inequality Degrade Democracy?
4. Does Income Inequality Obstruct Opportunity?
5. Does Income Inequality Lessen Longevity?
6. Does Income Inequality Hinder Happiness?
7. Is Income Inequality Harmful?
8. People Want Less Inequality, But It’s Not a Priority for Them
9. Inequality Reduction in Rich Nations May Impede Reduction of Worldwide Inequality
10. What About Wealth?
11. Inequality Reduction Should Be a Secondary Goal
12. How to Reduce Inequality