"Lux Radio Theater" broadcast a 60 minute radio adaptation of the movie on
December 3, 1951 with Ruth Roman reprising her film role.
Alfred Hitchcock bought the rights to the original novel anonymously to keep the price down, and got them for just $7,500.
Alfred Hitchcock had admired Edgar Allan Poe's stories since his teenage years, and went on to put Edgar Allan Poe references in his films. French critics noticed that there are connections between the runaway carousel in this film and Poe's "A Descent into the Maelstrom".
Alfred Hitchcock wanted to end the film with Guy (Farley Granger) saying "Bruno, Bruno Anthony - a clever fellow." But the studio forced him to shoot a happy ending.
Alfred Hitchcock: early in the film boarding a train carrying a double bass fiddle as Guy gets off the train (see also his cameo in The Paradine Case).
Raymond Chandler is credited as the main author of the script, but it was almost completely written by Czenzi Ormonde who was credited as second author.
Raymond Chandler seems to have gone out of his way to behave disagreeably to Alfred Hitchcock. When Hitchcock arrived at Chandler's home for a story meeting, Chandler hollered from his window, "Look at the fat bastard trying to get out of his car!"
Raymond Chandler's version of the script ended with Bruno Antony being arrested and institutionalized, with the final image being the villain writhing in a straight jacket.
Alfred Hitchcock's cameo in the film was directed by his daughter, Patricia Hitchcock.
As Guy leaves the last match, part of a quotation clearly including the words "two impostors" is visible on the beam above his head. It is from Rudyard Kipling's poem "If." The line reads "If you can meet with triumph and disaster / And treat those two impostors just the same..."
Film debut of Marion Lorne.
In the scene where Bruno searches for the cigarette lighter in the drain, Alfred Hitchcock personally selected the items of rubbish that lie on the floor.
The character of Bruno was named after Bruno Richard Hauptmann, the convicted kidnapper/killer of the Lindbergh baby.
The film did not initially end with Guy Haines and Anne Morton on the train. In another version of the film it ends just before this. This other reel was mistakenly labeled 'the British version' leading people to believe that this was what was shown in Britain. This is in fact incorrect and the same ending was broadcast in Britain and America.
The stunt where the man crawled under the carousel was not done with trick photography. Alfred Hitchcock claimed that this was the most dangerous stunt ever performed under his direction, and would never allow it to be done again.
The train station scenes in Metcalf were filmed at the former New Haven Railroad station, Danbury, Connecticut, which is today the home of the Danbury Railroad Museum.
There were several changes made from the original novel: the character Bruno Antony was named Charles Anthony Bruno and Guy Haines was an architect, not a tennis player. Also, Anne Morton was originally named Anne Faulkner.
This is the movie that determined the location of Carol Burnett's star on the Hollywood Walk of Fame. In 1951, she was working as an usher when this film was playing at the Warner Theatre on Hollywood Blvd. A couple arrived late, and Burnett, having already seen the film, advised them that it was a wonderful film that should be seen from the very beginning. The manager of the theatre very rudely fired her for this. Years later, when Carol Burnett was asked where she would like to have her star placed on the Hollywood Walk of Fame, she requested that it be placed in front of that theatre.
This was the last full feature for Robert Walker who died eight months after filming finished from an allergic reaction to a drug.