Capital in the Twenty-First Century

by Thomas Piketty

When the rate of return on capital exceeds the rate of growth of output and income, as it did in the nineteenth century and seems quite likely to do again in the twenty-first, capitalism automatically generates arbitrary and unsustainable inequalities that radically undermine the meritocratic values on which democratic societies are based.

is the primary source of data for this book.24

Knowledge and skill diffusion is the key to overall productivity growth as well as the reduction of inequality both within and between countries.

In short, the principal force for convergence—the diffusion of knowledge—is only partly natural and spontaneous. It also depends in large part on educational policies, access to training and to the acquisition of appropriate skills, and associated institutions.

The importance of capital in the wealthy countries today is primarily due to a slowing of both demographic growth and productivity growth, coupled with political regimes that objectively favor private capital.

In the developed countries today, the capital / income ratio generally varies between 5 and 6, and the capital stock consists almost entirely of private capital.