In this monograph, Brigadier General (retired) Russ Howard and Ms. Colleen Traughber  delve into the nexus between violent extremist elements and transnational criminal elements by first clarifying whether a real problem exists, and if so, what is the appropriate role for Special Operations Forces (SOF) in confronting it. The authors bring rigor to the subject matter by dissecting the issue of intention and opportunities of criminal organization and violent extremists. The authors note the wide variance in the motivations and opportunities of both different criminal organizations and extremist organizations. And make clear that the trafficking of humans, weapons, drugs, and contraband (HWDC) is a natural way for the criminals and extremists to cooperate. To bring the issue into focus, the authors systematically examine case studies dealing with the nexus between specific organizations and HWDC trafficking opportunities. The authors transition from the vignettes to how this nexus will impact SOF and interagency partners. They then identify issues for SOF including the traditional delineation between law enforcement activities and military activities.