Rob Sampson’s “Disparity and Diversity in the Contemporary City” establishes two very critical points for sociologists generally, and for scholars of the city in particular. First and foremost, it highlights the importance of individual perception, a form of cognitive processing, as a key determinant in social outcomes. While not entirely new, this claim is in need of serious re-consideration and further discussion in sociology today. Second and most innovatively, if not importantly, Sampson introduces a concern with perception into studies of the city and applies it to the phenomenon of segregation, both income and race-based. By so doing, he extends the role of perception and cognition beyond the domain of subjective urban experience, a subarea of study already well-developed in the work of the urban sociologist Claude Fischer. Sampson argues provocatively that perceptions of social disorder are central to the reproduction of neighborhood composition and urban socio-spatial form. Above and beyond his fascinating findings about the race-linked interpretive biases that drive individuals to perceive greater social disorder in certain neighborhoods than actual empirical evidence would dictate, Sampson’s research will bring the discipline of urban sociology more in line with recent innovations in brain and cognitive science that are changing the way many established fields are coming to understand individual thought and behavior.