 The film is based upon the novel "DEntre les Morts" (From Among the  Dead) which was written specifically for Alfred Hitchcock (I) (qv)  by Pierre Boileau (qv) and Thomas Narcejac (qv) after they heard  that he had tried to buy the rights to their previous novel "Celle  qui nétait plus" (She Who Was No More), which had been filmed as  _Diaboliques, Les (1955)_ (qv).