The Dark Invader

The Dark Invader is indeed an intelligence classic - a first-hand report by a top German intelligence agent sent to the still-neutral United States in the First World War. Rintelen's orders in Berlin had called for measures to prevent the shipment of American war material to Germany' enemies. In the US, this meant buying arms to keep them from being purchased by the Allies, but it could also mean placing bombs in the hulls of ships sailing for Europe and fomenting strikes among the labour force of American ammunition manufacturers.