In the 1940s, as Mexican families trekked north to the United States in search of a better life, tens of millions also left their towns and villages for Mexico’s major cities. In Mexico City migrant families excluded from new housing programs began to settle on a dried-out lake bed near the airport, eventually transforming its dusty plains into an informal city of more than one million people. In Informal Metropolis David Yee uncovers how this former lake bed grew into the world’s largest shantytown—Ciudad Nezahualcóyotl—and rethinks the relationship between urban space and inequality in twentieth-century Mexico. By chronicling the residents’ struggles to build their own homes and gain land rights in the face of extreme adversity, Yee presents a hidden history of land fraud, political corruption, and legal impunity underlying the rise of Mexico City’s informal settlements. When urban social movements erupted across Mexico in the 1970s, Ciudad Nezahualcóyotl’s residents organized to demand land, water, and humane living conditions. Though guided by demands for basic needs, these movements would ultimately achieve a more lasting significance as a precursor to a new urban citizenry in Mexico. In the first comprehensive history of modern housing in Mexico City, Yee challenges widely held assumptions about urban inequality and politics in Mexico.