The chapters in this volume contribute insight and increased understanding of the dynamic processes in street gang participation and the evolving forms of these groups. Additional chapters address the implications of different gang definitions and describe patterns of gang activity and varieties of group organization. The research reported in this volume represents both qualitative and quantitative strategies, including several instances of cross-cultural comparisons as well as mixed methods approaches. Some of the chapters rely on single sites while others reflect the Eurogang emphasis on the need for multisite studies. Chapters in this volume draw from studies conducted in a variety of nations, including England, Sweden, the Netherlands, Belgium, Israel, Venezuela, and the United States. This volume contributes to the evolving body of gang research in multiple regional, cultural, and methodological contexts.