During the Second World War, the FDR administration placed the FBI in charge of political surveillance in Latin America. Through a program called the Special Intelligence Service (SIS), 700 agents were assigned to combat Nazi influence in Mexico, Brazil, Chile, and Argentina. The SIS s mission, however, extended beyond countries with significant German populations or Nazi spy rings. As evidence of the SIS s overreach, forty-five agents were dispatched to Ecuador, a country without any German espionage networks. Furthermore, by 1943, FBI director J. Edgar Hoover shifted the SIS s focus from Nazism to communism. Marc Becker interrogates a trove of FBI documents from its Ecuador mission to uncover the history and purpose of the SIS s intervention in Latin America and for the light they shed on leftist organizing efforts in Latin America. Ultimately, the FBI s activities reveal the sustained nature of US imperial ambitions in the Americas."