This chapter builds on the findings presented throughout the book and reflects on their implications for theory and policy. While the ISRD4 project offers multiple opportunities for exploring theoretically relevant variables, the focus of this book has been on the characteristics of victimization and offending. These show that online modalities have not—yet—overtaken offline experiences and that there are some significant variations between countries. The design of the questionnaire allows for the study of the consequences of victimization and offending as much as their causes, and the sampling strategy invites multilevel modeling focusing on the impact of class and school characteristics. Regarding policy, the results on the overlap between victimization and offending suggest that a holistic trauma-focused approach to young people will be the most effective. Additionally, policymakers should be alert to the frequent overlap between offline and online forms of crime. Also, the prevalence and incidence of violent crimes is lower than for property crimes; thus, while not losing the former from view, this counsels against bowing to public pressure and moral panics regarding violent offenders. Finally, we review some of the challenges to conducting multinational research projects and describe ways we have sought to address them.