Gentrification is one of the most controversial issues in American cities today. But it also remains one of the least understood. Few agree on how to define it or whether it is boon or curse for cities. Gentrification has changed over time and has a history dating back to the early 20th century. Historically, gentrification has had a smaller demographic impact on American cities than suburbanization or immigration. But since the late 1970s, gentrification has dramatically reshaped cities like Seattle, San Francisco, and Boston. Furthermore, districts such as the French Quarter in New Orleans, New York City’s Greenwich Village, and Georgetown in Washington DC have had an outsized influence on the political, cultural, and architectural history of cities. Gentrification thus must be examined alongside suburbanization as one of the major historical trends shaping the 20th-century American metropolis.