From homes and offices to city streets, the spaces we inhabit change us more than we change them. Using insights from psychology, design, and architecture, Lily Bernheimer shows how the built and natural worlds subtly influence our behavior, health, and personality. Exploring such ideas as "ruin porn" and "ninja-proof seating," Bernheimer makes the case that buildings support our well-being best when they echo our natural habitats in some way. As people shape their environs together—resulting in "collective efficacy"—it creates communities with less litter, vandalism, and violent crime.