The subject of trauma and the nervous system, more particularly trauma to the head, has undergone considerable revision in recent years. More accurate investigation of the pathologic changes of concussion of the brain, increasingly objective clinical studies and the introduction of encephalography have enriched with facts a subject which hitherto was to a large extent in the realm of opinion. None the less there is still considerable dispute among competent neurologists as to what is and what is not objective evidence, and opinion, if not bias, still bridges gaps which should be filled in with facts. The relation of trauma to the nervous system and its sequels is complicated not alone by difficulties of diagnosis but by medicolegal problems and by difficulties in medical and social management. The problem is further complicated by the fact that most human beings are easily suggestible and that trauma occasionally offers an escape from