Thomas Piketty, a French economist, is most famous for his work on wealth inequality and the distribution of wealth. In his groundbreaking book Capital in the Twenty-First Century (2013), Piketty argues that wealth inequality has been rising for decades, especially in advanced economies, and that this trend is largely driven by the rate of return on capital (like investments and property) exceeding the rate of economic growth.

According to Piketty, this means that those who own capital (the wealthy) see their wealth grow faster than the overall economy, leading to an accumulation of wealth among the richest individuals and families. Meanwhile, those who rely primarily on labor income (wages, salaries) do not see their incomes grow as rapidly, which exacerbates inequality.

Piketty also discusses the historical patterns of wealth distribution, showing how inequality surged in the 19th century, fell during the mid-20th century (especially after World War II), and has been rising again since the 1980s. He argues that without intervention, this trend could continue, leading to a concentration of wealth in the hands of a small elite.

To address these issues, Piketty advocates for progressive taxation, particularly on wealth and inheritance, to reduce inequality and prevent the concentration of wealth from destabilizing society. He believes that such policies are necessary for creating a more equitable society, fostering social mobility, and ensuring sustainable economic growth.

His work has sparked significant debate about the causes and solutions to wealth inequality, and many have praised his data-driven approach to understanding the issue.