The traumatic neurosis syndrome may be viewed as a fundamental, nonspecific organismic reaction to severe external stress. Study of a group of patients led to the observation that this syndrome may be initiated in circumstances in which the patient experiences a brief forewarning of an impending catastrophe, or in circumstances precluding warning in which an accident takes place completely unexpectedly. In both instances psychological and physiological alarm mechanisms are set into action but are not appropriately discharged. Free-floating anxiety and continuing tension result. The descriptions point up the importance of external stress in contrast to the primacy of the reacting organism, usually formulated for the genesis of neurotic symptoms.