The discussion in this chapter is organized around a simple but fundamental aspect of urban life: What can people do together and under what circumstances? From this question stem the critical dimensions of urban policy in terms of who residents have to deal with, talk to, be intruded upon or intruding: who does space belong to, who has access to what kinds of space for what purposes? As soon as these considerations are opened up a wide range of political, administrative, and technical considerations about how cities are run also become more contestable and specific.