Cities are diverging in our contemporary era. Specifically, we use our analysis of Copenhagen and Houston to argue that cities exist for one of two reasons: for markets or for people. Market Cities (such as Houston) are dedicated to an unfettered free market ethos, individualism, and tolerance of high levels of inequality and decentralized governance, among other characteristics. By contrast, People Cities (such as Copenhagen) have a much greater collective ideal that drives the city toward attenuating inequality, strengthening government, and sanctioning “people-focused” policies and urban form. The first four chapters of the book showcase “how it happens” by introducing the perspective and studying the histories of the cities. We also showcase how government deeply shapes each type of city as well as the critical role that residents play in underpinning or contesting their city. The second part of the book (chapters 5 through 9) investigates “why it matters.” We discuss the implications of living in a Market City or People City for transportation, land-use planning, the environment, diversity, inequality, segregation, crime, and immigration. We also extend our perspective to a wider range of cities, making suggestions on how to apply the ideas presented in the book. Finally, we conclude by discussing how social change within the city might occur and best be accomplished.