This paper summarizes the main findings and perspectives emerging from a collective research project on the dynamics of income and wealth distribution. The primary objective of this project is to construct a high-quality, longrun, international database on income and wealth concentration, using historical tax statistics. The resulting database now includes annual series covering most of the twentieth century for a number of (mostly Western) countries. 1 The main motivation for this project comes from a general dissatisfaction with existing income inequality databases. Existing international databases display little homogeneity over time or across countries. They cover only a few isolated years per country, generally restricted to the post-1970 or post-1980 period. They almost never offer any decomposition of income inequality into a labor-income and a capitalincome component. Economic mechanisms can be very different for the distribution of labor income (demand and supply of skills, labor market institutions, etc.) and the distribution of capital income (capital accumulation, credit constraints, inheritance law and taxation, etc.), so that it is difficult to test any of these mechanisms using existing data. The fact that existing data are not long run is also problematic, because structural changes in income and wealth distribution often span several decades.

Using large samples of estate tax returns, we construct new series on wealth concentration in Paris and France from 1807 to 1994. Inequality increased until 1914 because industrial and financial estates grew dramatically. Then, adverse shocks, rather than a Kuznets-type process, led to a massive decline in inequality. The very high wealth concentration prior to 1914 benefited retired individuals living off capital income (rentiers) rather than entrepreneurs. The very rich were in their seventies and eighties, whereas they had been in their fifties a half century earlier and would be so again after World War II. Our results shed new light on ongoing debates about wealth inequality and growth.