World War I (1914–1918), however tragic, was nonetheless an “edifying school of nervous system experimental pathology” not only because of the various types of injuries, but also because their numbers were greater than any physician could have foreseen. The peripheral nervous system, the spine and the brain were all to benefit from the subsequent advances in clinical and anatomo-functional knowledge. Neurosurgeons took on nerve sutures, spinal injury exploration, and the localization and extraction of intracranial foreign bodies. Little by little, physical medicine and rehabilitation were established. A few of the most famous Parisian neurologists at the time—Jules and Augusta Dejerine, Pierre Marie, Joseph Babiński and Georges Guillain, who directed the military neurology centers—took up the physically and emotionally exhausting challenge of treating thousands of wounded soldiers. They not only cared for them, but also studied them scientifically, with the help of a small but devoted band of colleagues. The examples presented here reveal their courage and their efforts to make discoveries for which we remain grateful today.