Book excerpt: This book is a companion piece and extension of an earlier analysis of parent and friend relations, their structure and functions in children's social and personal development (James Youniss, Parents and Peers in Social Development: A Sullivan-Piaget Perspective, University of Chicago Press, 1980) The present book focuses on adolescents in these same relations. It presents two kinds of material: first, adolescents' own descriptions of interactions they have had in these relations, and second, theory regarding what these relations are and how they contribute to development. As before, relations are treated in the ideal typical sense as descriptions are synthesized across subjects to yield average charateristics that define structure.