Thomas Piketty explains the grand dynamics that drive the accumulation and distribution of capital. In Capital in the Twenty-First Century, Piketty analyzes a unique collection of data from 20 countries, ranging as far back as the 18th century, to uncover key economic and social patterns. He makes the case that the main driver of inequality—the tendency of returns on capital to exceed the rate of economic growth—threatens to generate extreme inequalities that foment social and political turmoil and undermine democratic values.