This 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. Official German records, captured by British and American forces at the end of the Second World War, clearly show the colourful memoirs of the German naval officer to be accurate. Von Rintelen's orders in Berlin had called for measures to prevent the shipment of American war material to Germany's 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. Captain Franz von Rintelen most likely would have kept his secrets to himself, had he been treated more tactfully when returning from years of British and American imprisonment. The memoirs, not entirely free of emotion, are therefore also an attempt to tell what Berlin stubbornly denied had happened.
As might be expected, the German Foreign Office and powerful men in the Nazi government were able to quash publication in Germany, thereby forcing von Rintelen to seek a publisher abroad. Embroiled in a bitter legal dispute with his government over financial claims arising from his activities in the US, von Rintelen wisely left the country, probably just in time to avoid arrest by the National Socialists. The officer of the Imperial German Navy now moved to London. He befriended 'Blinker' Hall, his former captor in the First World War, and asked if he could don a British uniform and join the fight against Germany.