Capital in the Twenty-First Century, by Thomas Piketty

Income disparity in the developed world is approaching levels seen only in predemocratic times. Though the spread of educational opportunities has a leveling effect, the income gap is likely to continue to expand—eventually undermining the viability of democratic capitalism.

This stark message from French economist Thomas Piketty has made his extensively documented book a best seller and the object of much scholarly and popular scrutiny. He foresees social unrest arising from increasing income disparities and believes the political dysfunction present in the United States and elsewhere can be attributed to a looming battle between those who seek to protect the income disparity and those who seek to counter it.

The documentation of his thesis is no simple matter. The data presented include charts and graphs that cover the 20th century and in some cases go back to the 18th. Of chief importance is data on the percentage of national income received by the top 10 percent of United States citizens over the past century.