The importance of peer groups is explained with reference to the biographical phase, gender-specific roles, and family and school contexts. Surveys of peer groups between 1977 and 1987 show that changes in the structure and content of peer group relations are intertwined in the sequence of biographical stages with changes in the significance and relevance of peer group networks. These changes represent structural transformations in adolescence that occur against the background of transformations and relocations in a work-oriented society. Peers and the social relations network take on new and often indispensable functions for life management which, for some adolescents and young people, become compensating agents for a lack of institutional services to facilitate the process of growing up. At the same time, peers and the social relations network maintain their functions of emotional support, providing partners for recreation, and offering a frame of reference for confrontation and experiments with generation-specific norms and values. Surveys also indicate the socioecological differentiation of peer groups; peer groups in a modern, suburban housing area, for example, probably have a different significance from peer groups in a small rural town. Regionally-specific differentiations become concrete in various life management patterns of adolescents and young adults. In terms of the sociopolitical function of peer groups, a youth policy is needed that supports and expands both opportunities and resources for adolescent and young adult life management. Such a policy should improve housing, career, employment, and social conditions. 16 references.