Why were some soldiers tried and executed by their own military authorities during World War I? Using previously unpublished source material, the author has been able to throw light on one of the most sombre episodes of the Great War. Besides reviewing the history of the events themselves, the author also examines the struggle with the military authorities to clear the soldiers names, beginning in the period between the two world wars. By the 1960s, the public image of the executed soldiers had begun to change. It would culminate in the British campaign to grant them an official pardon and in the French decision to remember them a ceremony. How, he asks, did these changes come about? Nicolas Offenstadt is a graduate of the Institut des Etudes Politiques, in Paris. He holds an agrégation in history and is a member of the Thiers Foundation.