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The source story for this film, Casting the Runes, was also adapted into a radio play of the same name for the anthology radio program, Escape. The story was also adapted twice for British television, first as Casting the Runes (1968) of the anthology series Mystery and Imagination (1966), and again as Casting the Runes (1979) of ITV Playhouse (1967). Of late, it was also ostensibly the plot (and obviously ending) of Sam Raimi's Drag Me to Hell (2009), credited as written by him and his brother, with no mention of it even inspired by M.R. James' original story, nor even this film.
Jacques Tourneur never planned to show the monster, but to leave it instead to the audience's imagination. However, the studio insisted that the monster be shown, and added it in post-production, allegedly without Tourneur's consent, approval, or involvement.
"The scenes where we really see the demon were shot without me. All except one: I shot the sequence in the woods where Andrews is pursued by this sort of cloud." [Tourneur himself in Midi-Minuit Fantastique 5.65]. He also said, "It should have been unveiled bit by bit without it ever really being shown." [in Cinefantsatique; '73.]
Dana Andrews was so impressed with director Jacques Tourneur that when he returned to the United States he had Tourneur direct his next film, The Fearmakers (1958).
Charles Bennett was angry at the changes made to his script by producer Hal E. Chester. In an interview, Bennett said, "If [Chester] walked up my driveway right now, I'd shoot him dead."
Ray Harryhausen was contacted to create the effect scenes with the demon, but he was already committed to his project The 7th Voyage of Sinbad (1958) with producer Charles H. Schneer.
Beginning in the 1980s, Columbia Pictures replaced their edited 83-minute U.S. version with the uncut original 95-minute version whilst retaining the U.S. title "Curse of the Demon." The various video releases, and pay-TV showings, have used this restored version. A DVD release contained both versions.