"Capital in the 21st Century" renews contemporary economic thought and its prospects, in the same way that Karl Marx's work of the same title did in the 19th century. The 20th century was initially marked by a reduction in inequalities. Wars caused an unprecedented redistribution of accumulated wealth. However, growth in peacetime led to an increase in inequalities, as the return on capital is greater than the rate of economic growth. At the same time, a new phenomenon exacerbates inequalities: the skyrocketing, beyond all reason, of the remuneration of the elite managers. Additionally, large fortunes secure higher returns the greater the initial accumulation of wealth. The result is a continuous widening of inequalities, bringing our world back to the extreme point it was at before the outbreak of World War I. The principles of meritocracy and social justice are retreating.

Piketty does not limit himself to scientific description but attempts a major political intervention. His response is articulated with combative clarity: international cooperation is needed to impose a global tax on capital. This is an urgent necessity, as the increase in inequalities constitutes a direct threat to democracy. With his acumen, the volume of data, the depth, and historical scope, but above all with his clear view of the great invisible forces of economy and history that determine the evolution of states and societies, "Capital in the 21st Century" is the most imposing work of scientific research in economic studies of our century, this century that began with the fall of the Berlin Wall and the creation of the first truly global capital market in history. Beyond this, however, Piketty re-baptizes economics in its foundational origins: he reminds us of their inseparable connection with the field of social sciences and debunks the myth of the disconnection of economic analysis from politics.