Includes bibliographical references (p. 141-167) and index.

Peers in the Life Course -- Cross-cultural Variation in Peer Interaction -- Historical and Structural Variation -- Social Structure -- Industrial Societies -- Changing Peer Relations -- Peers as Agents of Socialization -- Peer Group Formation -- Parents versus Peers -- The Group Character of Crime and Delinquency -- Delinquency as Group Behavior -- Features of Delinquent Groups -- Other Features of Delinquent Groups -- Do Groups Matter? -- Peers and Delinquent Conduct -- Fear of Ridicule -- Loyalty -- Status -- Ridicule, Loyalty, and Status -- Crime as Collective Behavior -- Anonymity -- Diffusion of Responsibility -- Delinquency as "Rowdy" Behavior -- The Group as Moral Universe -- Mechanisms of Consensus -- Sutherland's Theory of Differential Association -- Evaluating the Theory -- Social Learning Theory -- Cross-Sex Peer Influence -- Groups, Drugs, and Delinquency -- Boredom -- Groups as Protection -- Co-offenders and Opportunity -- The Virtual Peer Group -- Applying Peer Explanations of Delinquency -- Age and Crime -- Peers and the Life Course -- Age, Peers, and Identity -- Parents, Peers, and Delinquency -- The Contest between Parents and Peers -- Gender and Delinquency -- Peers and Public Policy -- Pending Questions -- Old Friends -- Age and Co-offending -- Heterogeneity of Motivation in Groups -- Structural Variation in Peer Associations -- Inferring Peer Influence -- Qualifications and Clarifications.

The principal thesis of Companions in Crime is that deviant behavior is predominantly social behavior.