At the outbreak of the First World War, Emile Herzog was a busy 36-year-old textile merchant who had all but renounced his one-time literary ambitions in order to work for the family business in Normandy. At the end of his long life, now under the pseudonym of André Maurois, he was not only a celebrated author of a great number of books and a member of the Académie Française, but also, and perhaps crucially, a publicly renowned authority on all things British. This transformation is down to an experience of cultural and linguistic transfer. Reluctantly at first – he explains the little English he had acquired from an Irish governess did not really equip him for the post – Herzog was called up in August 1914 to serve as military interpreter alongside the British troops in France. He experiences transfer, cultural and linguistic, in several contexts: in his daily work as a go-between dealing with French civilians and British officers, which can be retraced in his personnel file at the French military archives in Vincennes ; by translating and publishing with his immediate superior, liaison officer Georges Richet, one of the first British accounts of the war ; and finally by writing what would become the starting point of his literary career : the humorous, semi-autobiographical account of life with the British Army in France, Les Silences du Colonel Bramble (Paris, 1918). While his publishing activity during the Great War has an explicit and fairly narrow focus – making the French public aware of the British contribution to the War effort – this broadened gradually as his success enabled him to publish a wider range of texts. This includes very successful biographies of famous Brits, including Keats, Shelley and Dickens, but also more journalistic texts, such as advice to young Frenchmen traveling to Britain. André Maurois was not only a prolific writer of biographies. He also applied the same energy to autobiographical writing, publishing subsequent editions of his memoirs between 1928 and 1970. When read in conjunction with the several stages of manuscripts conserved at the French National Libraries‘ Richelieu site, they clearly show an individual fleshing out his role as an intercultural agent. Our paper proposes to retrace this autobiographical construction of an intermediary figure, using recent work on autobiography by Philippe Lejeune. What is the place of the original experience of transfer during the war in this discourse of legitimization? How does it relate to the fictional interpreter Aurelle in Les Silences du Colonel Bramble? What does this case tell us about the larger milieu of French experts on Great Britain during the interwar years who had similar experiences during the First World War (including André Siegfried and Daniel Halévy)?