In 2011, Robert Sampson, a professor of social sciences at Harvard, received the Stockholm Prize in Criminology, the field’s equivalent of a Nobel. Last year he published his magnum opus, Great American City: Chicago and the Enduring Neighborhood Effect (University of Chicago Press, 2012), based on his research as scientific director of the Project on Human Development in Chicago Neighborhoods. Sampson helped pioneer the concept of collective efficacy, a measure of neighbors’ willingness to act for each other’s benefit. He sees it as having as strong an effect on children’s well-being as do families, poverty, and schools.