Becky and Miles paraphrase Shakespeare twice. "I know a bank whereon the wild thyme blows, Where oxlips and the nodding violet grows" is from A Midsummer Night's Dream. "That way madness lies" is from King Lear.
Don Siegel was very against the optimistic outcome of the movie, but the decision to give hope to the audience was forced upon him by the studio. Most people dislike the ending, agreeing with Siegel's original intention to end the film with Miles trying to warn people of the alien invaders, in vain.
Throughout the years, Sam Peckinpah (who appears briefly in the film as the meter reader) claimed that he had done work on the script ranging from modifications to major overhauls. Those who worked on the film claimed that if Peckinpah had made any changes to the script, it was limited to a few lines of dialog. Peckinpah's claims became so inflated that the actual writer, Daniel Mainwaring, threatened to file an official complaint with the Writers Guild of America, so Peckinpah backed down. When Peckinpah died in 1984, many of his obituaries still carried the claim that he had rewritten the screenplay for this film.
Universal's UK DVD (824 346 1.11) comes with a choice of the original black and white or a colorized version. The black & white's running time is 1hr and 20 mins while the color version has an added five minutes to its running time.
In 1994, Invasion of the Body Snatchers (1956) was selected for preservation in the United States National Film Registry by The Library of Congress as being "culturally, historically, or aesthetically significant."
Filming was supposed to commence in Mill Valley, north of San Francisco, but the budget couldn't allow it. In fact, several locations made up the town of Santa Mira, including Sierra Madre, Chatsworth, Glendale, Los Feliz, Bronson and Beachwood Canyon. As well as the Allied Artists studio lot on the east side of Hollywood.
The film was almost called The Body Snatchers after Jack Finney's serial, but it sounded too similar to the Val Lewton film The Body Snatcher (1945). After several titles like They Come from Another World, Better Off Dead, Sleep No More, Evil in the Night and World in Danger, the studio finally settled on Invasion of the Body Snatchers.
Producer Walter Wanger wanted a Winston Churchill quotation as a preface, with Orson Welles doing the narration. When they couldn't persuade him, Wanger tried to enlist science-fiction author Ray Bradbury. He declined as well.
During test screenings, much of the film's original humour and humanity was cut when the audience found the film difficult to follow and laughed at all the wrong moments. The studio insisted on edits because it wasn't policy to mix humour with horror.
During its original cinema release, paper-mache pods were on display in the lobbies, as well as black & white cutouts of Kevin McCarthy and Dana Wynter running frantically away from a crowd of pod-people.
Kevin McCarthy and author Jack Finney have always denied the belief that the story is a metaphor against McCarthyism and Communism. They just saw it as a thriller. Don Siegel however believes the political references to Senator McCarthy and totalitarianism are inescapable, even though he tried not to emphasize them.
Screenwriter Daniel Mainwaring had brushes with Hollywood witch-hunts, which lends credence to the theory that the film is an unconscious metaphor against McCarthyism. Something Dana Wynter agreed with, although she didn't recall the mention of any political statements on-set. Kevin McCarthy believed the film to be an attack on "Madison Avenue" attitudes. Siegel joked that the pods represented the front office.
Even though the film was "Produced in Superscope" according to the opening credits and released in the 2.00:1 aspect ratio, the film was actually shot with the spherical 1.85:1 aspect ratio in mind. The scope prints were created in the lab in post-production by cutting off the top and bottom of the image. Director Don Siegel protested the reformatting to no avail.
The trivia item below may give away important plot points.
The film originally ended with Miles J. Binnell on the highway shouting to the people driving by, "You're next, you're next!" However, the studio wanted a happier ending that would assure the audience that the hero's efforts were not in vain, so scenes were added to the opening to show Miles in a hospital recounting his story to two other doctors and to the end when the other doctors find out about the pods and one of them contacts the FBI.