This is a clear, concise introduction to global inequality for the general reader. There are three sections, each beginning with a short essay on economics and then following it with a number of bite-sized vignettes to illustrate what he's been talking about. It's a good way to teach the subject, and this is as good a place as any to be introduced to such names as Pareto, Kuznets and Gini.
The first section deals with inequality of income within nations. For a long time this was declining in developed countries, but for the last thirty years it's been rising again. The second section looks at inequality between nations. This is far greater than it was 100 years ago, but is it starting to decline? How much weight do we give China and India? The third section is about inequality between individuals at a global level. Where do you stand you in the world-wide distribution of wealth? Turns out I'm in the top 20%, but not the top decile. Interestingly, Milanovic shows that the world-wide distribution of wealth used to be mainly determined by social class, but now 80% of it is down to which country you were born in.
Of course there are omissions. This is a short, introductory work. It traces trends in inequality without trying to do much to explain them. It focuses on inequalities in income, rather than wealth. But this is a great place to start and will leave you with plenty of questions to explore further (about immigration, for instance). And it's refreshing to hear a well-placed establishment economist (Head of Research at the World Bank) admit that inequality studies are unpopular because they 'are not particularly appreciated by the rich'.