Cover legend: The social world of humans is complex and places great processing demands on the brain. The cover illustrates an individual's social network, generated by the Facebook application Nexus. Each white node in the graph represents a person, and the edges connecting them are colored to emphasize differential social closeness—blue edges, clustered around the enlarged white center node, represent close social bonds, while bonds with those who are less socially close are colored orange. In their paper, Krienen et al. find that brain systems including medial prefrontal cortex (MPFC) are preferentially responsive when making inferences about others who are socially close to us, even if we believe we do not share their views. For more information, see the article by Krienen et al. in this issue (pages 13906–13915).