On the Nightmare is a searching investigation of this mysterious, often terrifying phenomenon. Curiously enough, no disorder in the history of medical science has evoked such consistent superstition on the part of layfolk--even today, when nearly every one of us is still unconsciously superstitious, as our customs of knocking wood, crossing fingers and Friday the Thirteenth readily prove. In explaining the weird nightmare occurrences, all peoples and faiths have invoked mythological creatures: werewolves, vampires, incubi, and succubi (stealthy ravishers of the night), devils, witches, etc. The modern psychological theory of the nightmare is mainly the product of the researches of Sigmund Freud. Dr. Ernest Jones draws for this definitive study upon psychiatry, history, literature and mythology. As a result of these investigations, he has evolved an important theory concerning the relationship between religion, upon whose unconscious significance these superstitions throw light, and the burden of guilt inherited by everyone "from the deepest stirrings of mental life, the primordial conflict over incest." As President of the International Psychoanalytical Association and author of numerous widely-read books and articles, he is one of the world's leading authorities on psychiatry and related studies.