The studies in this book examine the processes through which transnational criminal justice norms are being formed and institutionalized, migrate across jurisdictions, and shape the practices and attitudes of national and local actors. They assess the driving forces behind the emergence of new mechanisms of transnational legal ordering in diverse areas of criminal justice, analyze their limits and their effects, and evaluate their implications for our understanding of the nature of criminal law as a social and political institution. This introductory chapter sets the analytic framework for these inquiries. Drawing on the book’s case studies, we explore a number of theses for explaining why illicit activities and law enforcement practices become objects of transnational regulation. We consider how competition among and resistance within transnational legal orders shape and constrain their formation, institutionalization, and consequences. Finally, we highlight the book’s contribution to the broader project of developing a socio-legal theory of transnational legal ordering and to scholarly debates regarding the impact of globalization on criminal justice policies.