For nearly a century, preservation advocates have argued the historical significance of specific buildings and districts in American cities, securing protective governmental regulations. The hundreds of resulting districts reveal the past through details such as historic architecture and appropriate paint colors. These districts have blocked waves of real estate development, which might have leveled the areas to create modern towers, parking lots, and highways. Historic districts have contributed to increasing property values, sometimes fueling gentrification of specific neighborhoods as well as heightened economic and racial segregation. This book critically evaluates case studies of the development of historic preservation in American cities over time.