Jules Crawford Silber (c.1885–1939) was a German mole inside the mail censorship division of British Intelligence during the First World War.
Before leaving New York City, he gave his letter-box's address to ambassador to the United States and high-level spymaster, Count Johann Heinrich von Bernstorff.
Silber carried official British documents, however, that showed his military service in South Africa and India, none of which mentioned his German nationality.
Obstructing MI5 investigations, he obtained a position at the mail censor's office after an interview by a British Army Colonel who had also served in Punjab region.
The French version of this book, published in 1968, was titled Le Plus Anglais des espions allemands (The Most English of German Spies).