Within the preparation framework of D-Day in France (Operation Overlord), General Eisenhower's Staff Officers, in March 1943, conceived and launched a plan entitled Sussex . This was to be set up in all the regions in the North of the Loire river, which would be battle zones. Teams of two officers, an observer and a radio operator, and be placed in strategic points. They would provide to the Allies, during and after D-Day, firm information on the German army, its order of battle, its troop movements and in particular those of the Panzer divisions, including heir supply depots of materials and ammunition. In addition the installation and launch pads of V1 and V2 Flying Bombs. The Allied Headquarters could then make the right informed decisions, intervening effectively and in particular the bombardment of convoys, concentrations of troops and materials. To achieve this mission, 120 volunteers, all French, were selected. They received intensive training during several months and were trained using the techniques of military intelligence by British instructors of the Intelligence Service (I.S.) and Americans of the Office of Strategic Services (OSS). The work of these agents was tough and difficult because the Gestapo and the German services of detection were increasingly powerful and many were arrested, tortured and shot. However the work carried out by all was admirable and America could declare after the war: The activity of Sussex agents was intense and the information transmitted of the utmost importance. The results obtained largely exceeded the most optimistic forecasts . THIS BOOK IS IN ENGLISH.