For years we have known that teenagers' peers influence their substance use. This book tells you how. It is not a simple explanation: it is based on the teenagers' own selection of peers, peer influence, the formation of social networks and the patterning of their peer ties. All of which can result in chain reactions in teenagers' substance use.

DEIRDRE M. KIRKE is Lecturer in Sociology at the National University of Ireland, Maynooth, Co. Kildare, Ireland, and is a member of the International Network for Social Network Analysis.