The working titles of Curse of the Demon were Night of the Demon, The Bewitched, Casting the Runes and The Haunted. The film opens with an image of a Stonehenge-like ruin over which an off-screen narrator states: "It has been written since the beginning of time even unto these ancient stones, that evil, supernatural creatures exist in a world of darkness. And it is also said man using the magic power of the ancient runic symbols can call forth these powers of darkness, the demons of hell."

Curse of the Demon was produced at Associated British Picture Corp. Studios, which is abbreviated on the print as A.B.P.C. The Copyright Catalog lists the film's running time as 95 minutes, which according to a modern source, was the running time of the British release.

The Original screenplay of Curse of the Demon was written by Charles Bennett, who is best known for his script collaborations with Alfred Hitchcock on Blackmail (1929), The 39 Steps (1935), Secret Agent (1936), the 1934 version of The Man Who Knew Too Much, Sabotage (1936), Young and Innocent (1937) and Foreign Correspondent (1940).

Bennett was very unhappy with what Hal E. Chester did to his screenplay for Curse of the Demon: "I had to sit by while Chester made the biggest balls up of a good script that I have ever seen...somehow the movie, perhaps because the fundamentals of my screenplay couldn't be entirely wiped out, succeeded. To add insult to injury I frequently get letters, even now, from cult-type organizations, asking me to write something about Night of the Demon because it is still loved in peculiar areas."

Despite Bennett's low opinion of Chester's changes to his screenplay, he had great respect for the director Jacques Tourneur, saying, "Tourneur was a wonderful person. I would never blame him for what happened to the film. I blame only Hal Chester. Never Jacques. He did the best he could with what he was told to shoot."

Curse of the Demon is the movie that the line "It's in the trees! It's coming!" was sampled from for the opening of the Kate Bush song "The Hounds of Love".

The scene in which Holden breaks into Karswell's study at night and is attacked by his housecat-turned-leopard is reminiscent of the scene in Cat People (1942), also directed by Jacques Tourneur, where Dr. Judd (Kent Smith) is attacked in his darkened study by a prowling panther.

Curse of the Demon was referenced in the opening song from The Rocky Horror Picture Show ("Science Fiction Double Feature"): "Dana Andrews said prunes gave him the runes, but passing them used lots of skill".

Dana Andrews was so impressed with the director that when he returned to the United States he had Jacques Tourneur direct his next film, The Fearmakers (1958).

Although he had appeared in numerous film noirs and thrillers prior to 1957, Curse of the Demon was really the first fantasy film that Dana Andrews appeared in. After that, he dabbled more frequently in the sci-fi horror genre with such efforts as The Satan Bug (1965), Crack in the World (1965) and The Frozen Dead (1966).

In interviews regarding Curse of the Demon, Dana Andrews credits the story to Oliver Onions. The story is actually based on "Casting the Runes" by M.R. James.

Jacques Tourneur's approach to horror was always more psychological than explicit. "The real horror is to show that we all live unconsciously in fear," he observed. "Many people suffer today from a fear that they don't begin to analyze and which is constant. When the audience is in the dark and recognizes its own insecurity in that of the characters of the film, then you can show unbelievable situations and be sure that the audience will follow. For another thing, people love to be afraid. It's strange, when we're children, we say to our nurse or to our parents: "Frighten us," and we love that. These fears stay in us all our life: we're afraid of thunder, we're afraid of darkness, of the unknown, of death. The horror film, if it's well done, awakens in the mind of the audience this fear that it didn't know it had in it, and this discovery makes it shiver."

When Curse of the Demon was first released in the U.S., it was distributed as a double feature with the Hammer horror film, The Revenge of Frankenstein (1958), directed by Terence Fisher.

Despite bearing the title Curse of the Demon, the print currently available on videotape and television in the USA is actually the original longer (UK) cut.

The original U.S. release version was edited down from the British version by thirteen minutes (some sources claim it was fourteen). Here are some of the deleted or drastically edited scenes, which can be seen in the British version:
- a conversation at the airport between Holden and the reporters was shorn of 41 seconds
- Holden's first meeting with his scientific colleagues is reduced by almost half its original length
- a minute and twenty one seconds was cut from the tense encounter between Karswell and Holden in the British Museum, lessening the impact of their clashing philosophies
- crucial dialogue between Joanna and Holden in a hotel room that helped confirm Holden's refusal to accept supernatural beliefs was deleted.

Compiled by Jeff Stafford

SOURCES:
Cult Movies by Danny Peary
Attack of the Monster Movie Makers: Interviews with 20 Genre Giants by Tom Weaver
Cinefantastique, "Tourner Remembers" by Joel E. Siegel
Jacques Tourneur: The Cinema of Nightfall by Chris Fujiwara
American Directors Volume 1 by Jean-Pierre Coursodon with Pierre Sauvage
Video Watchdog, "Curse of the Demon: Two Versions, Two Critics" by Bill Cooke and Kim Newman