This chapter seeks to place rational choice theories of crime into a broader context. This context considers how the larger structure of opportunities sets the stage for criminogenic choices as well as influences whether the choices result in successes or failures for those who make them. The chapter provides the rational structure of crime from the viewpoint of the analyst, not of the offender. Criminal opportunity can increase greatly if the changing physical structure of communities obstructs the watchful eye of parents. The routine activities of everyday life set the scene for the web of interaction between these people and between the crime target and any guardians. Informal control is tightest when all several elements are in direct physical contact and when relevant people know one another very well. The single-parent household gives the community only one parent to know and hence reduces the potential linkages that can be evoked for informal social control.