Organised crime covers a wide range of activities, including drug trafficking, illegal trafficking of people, and fraud. The existence of a land border does not impede these operations; instead in many cases it is used to their advantage. In response, law enforcement strategies must include a transnational, multi-agency approach. This book critically analyses the extent to which Northern Ireland and the Republic of Ireland have been successful in implementing effective action against transnational organised crime. It explores the adoption of key law enforcement strategies and measures in these jurisdictions, and evaluates how regional (EU law) and international (UN Convention) standards have been implemented at the national level. Drawing on interviews with over 90 stakeholders including the Department of Justice Northern Ireland, the Department of Justice and Equality in Ireland, the Police Service of Northern Ireland and An Garda Siochana, Tom Obokata and Brian Payne discuss the factors affecting the effective prevention and suppression of organised crime, particularly in relation to cross-border cooperation. In exploring challenges of transnational crime and cooperation, this book will be of great use to students and researchers in international and transnational criminal law, criminology, and crime prevention.