Capital in the Twenty-First Century is a 2013 book by French economist Thomas Piketty. It focuses on wealth and income inequality in Europe and the United States since the 18th century. It was initially published in French (as Le Capital au XXIe siècle) in August 2013; an English translation by Arthur Goldhammer followed in April 2014. The book’s central thesis is that when the rate of return on capital (r) is greater than the rate of economic growth (g) over the long term, the result is concentration of wealth, and this unequal distribution of wealth causes social and economic instability. Piketty proposes a global system of progressive wealth taxes to help reduce inequality and avoid the vast majority of wealth coming under the control of a tiny minority.