Mass migration to suburban areas was a defining feature of American life after 1945. Before World War II, just 13% of Americans lived in suburbs. By 2010, however, suburbia was home to more than half of the U.S. population. The nation’s economy, politics, and society suburbanized in important ways. Suburbia shaped habits of car dependency and commuting, patterns of spending and saving, and experiences with issues as diverse as race and taxes, energy and nature, privacy and community. The owner occupied, single-family home, surrounded by a yard, and set in a neighborhood outside the urban core came to define everyday experience for most American households, and in the world of popular culture and the imagination, suburbia was the setting for the American dream. The nation’s suburbs were an equally critical economic landscape, home to vital high-tech industries, retailing, “logistics,” and office employment. In addition, American politics rested on a suburban majority, and over several decades, suburbia incubated political movements across the partisan spectrum, from grass-roots conservativism, to centrist meritocratic individualism, environmentalism, feminism, and social justice. In short, suburbia was a key setting for postwar American life. Even as suburbia grew in magnitude and influence, it also grew more diverse, coming to reflect a much broader cross-section of America itself. This encompassing shift marked two key chronological stages in suburban history since 1945: the expansive, racialized, mass suburbanization of the postwar years (1945–1970) and an era of intensive social diversification and metropolitan complexity (since 1970). In the first period, suburbia witnessed the expansion of segregated white privilege, bolstered by government policies, exclusionary practices, and reinforced by grassroots political movements. By the second period, suburbia came to house a broader cross section of Americans, who brought with them a wide range of outlooks, lifeways, values, and politics. Suburbia became home to large numbers of immigrants, ethnic groups, African Americans, the poor, the elderly and diverse family types. In the face of stubborn exclusionism by affluent suburbs, inequality persisted across metropolitan areas and manifested anew in proliferating poorer, distressed suburbs. Reform efforts sought to alleviate metro-wide inequality and promote sustainable development, using coordinated regional approaches. In recent years, the twin discourses of suburban crisis and suburban rejuvenation captured the continued complexity of America’s suburbs.