The author establishes in a comparative study the etiological community of five clinical pictures, which may also replace one another during development. These are: pavor nocturnus, animal phobias, obsessive fear of the death of the parent of the same sex (a condition isolated and described by him in 1915), hysterical dread of death, and agoraphobia (fear of death in the street). He stresses the central significance of repressed aggression in their causation; aggressive components being converted into feelings of guilt, which result in castration anxiety in the child and dread of death in the adult.