This monograph analyzes United States Special Operations Forces’ (USSOF) assistance to Colombia in the context of decades of counterinsurgency and counternarcotics operations. While the case of Colombia is often cited as an exemplar of global Special Operations Forces (SOF) foreign engagement, the details of the engagement, and the reasons for its success, have not previously been addressed in a scholarly publication. This study represents the first comprehensive analysis of the persistent SOF engagement in Colombia. It draws upon the collective wisdom of numerous U.S. and Colombian government personnel, and the authors’ own decades of experience in Colombia and other countries where the United States has undertaken prolonged partnership.