In the last two decades, organised crime has grown more complex, posing evolving challenges for U.S. federal law enforcement. These criminals have transformed their operations in ways that broaden their reach and make it harder for law enforcement to combat them. They have adopted more-networked structural models, internationalised their operations, and grown more tech savvy. They are a significant challenge to U.S. law enforcement. This book examines a broad conceptualisation of organised crime in its narrative discussion of criminal activity. The analysis includes groups engaged in sustained criminal enterprises, such as, but not limited to: drug traffickers, mafia families, smugglers, violent gangs, and fraudsters. These operations may or may not have a transnational dimension to them, but they directly impact U.S. persons, businesses, and/or interests.