Piketty tries to apply this schema to many societies across time and space. His discussion is punctuated by many charts and tables: Using a combination of extrapolation and guesswork to produce quantitative estimates for eras that predate modern data collection is a Piketty trademark, and it’s a technique he applies extensively here, I’d say to very good effect. It is, for example, startling to see evidence that France on the eve of World War I was, if anything, more unequal than it was before the French Revolution.

But while there is a definite Francocentric feel to “Capital and Ideology,” for me, at least, the vast amount of ground it covers raises a couple of awkward questions.

The first is whether Piketty is a reliable guide to such a large territory. His book combines history, sociology, political analysis and economic data for dozens of societies. Is he really enough of a polymath to pull that off?

I was struck, for example, by his extensive discussion of the evolution of slavery and serfdom, which made no mention of the classic work of Evsey Domar of M.I.T., who argued that the more or less simultaneous rise of serfdom in Russia and slavery in the New World were driven by the opening of new land, which made labor scarce and would have led to rising wages in the absence of coercion. This happens to be a topic about which I thought I knew something; how many other topics are missing crucial pieces of the literature?

The second question is whether the accumulation of cases actually strengthens Piketty’s core analysis. It wasn’t clear to me that it does. To be honest, at a certain point I felt a sense of dread each time another society entered the picture; the proliferation of stories began to seem like an endless series of digressions rather than the cumulative construction of an argument.

Eventually, however, Piketty comes down to the meat of the book: his explanation of what caused the recent surge in inequality and what can be done about it.

For Piketty, rising inequality is at root a political phenomenon. The social-democratic framework that made Western societies relatively equal for a couple of generations after World War II, he argues, was dismantled, not out of necessity, but because of the rise of a “neo-proprietarian” ideology. Indeed, this is a view shared by many, though not all, economists. These days, attributing inequality mainly to the ineluctable forces of technology and globalization is out of fashion, and there is much more emphasis on factors like the decline of unions, which has a lot to do with political decisions.