Thomas Piketty's monumental work, translated from French and published in English in 2014, became an unlikely global bestseller by applying two centuries of tax and income data from twenty countries to the fundamental question of wealth distribution in capitalist economies. The book's central analytical claim — expressed in the formula r > g, meaning that the rate of return on capital historically exceeds the rate of economic growth — provides a structural explanation for why wealth tends to concentrate over time under capitalism unless disrupted by wars, depression, or deliberate redistribution policy. Piketty documents the dramatic compression of inequality during the mid-twentieth century — which he attributes primarily to the destruction of capital in two world wars and the depression rather than to the inherent self-correcting mechanisms of capitalism — and the subsequent return toward nineteenth-century levels of concentration in recent decades. The book generated intense debate among economists about the reliability of Piketty's data, the causal mechanisms he proposes, and the policy conclusions he draws, including his famous proposal for a global wealth tax. Whatever one concludes about those debates, Piketty's historical documentation of wealth distribution patterns across centuries provides essential context for understanding the economic environment in which long-term investors operate, and his work has fundamentally changed the terms of debate about inequality and capital in the modern economy.