sentences:  Jean Doise, of the École Normale Supérieure and a military professional with a strong technical background attempts to explain the genesis of the case through the development, between 1892 and 1897, of the French 75mm field gun.Doise proposes in "A Secret well guarded.Military History of the Dreyfus Affair" that Alfred Dreyfus had been used by French counterintelligence to distract German espionage from the French 75's secret development and furthermore that Esterhazy, who once served in military counterintelligence, had played a role in this manipulation.