Henri Attal and Dominique Zardi had the roles "Men in Boat" but were cut from the final released print.
Alfred Hitchcock hired Leon Uris to adapt his own novel. But Uris didn't care for Hitchcock's eccentric sense of humor, nor did he appreciate the director's habit of monopolizing all of his time as they worked through a script. Hitchcock was disappointed that Uris seemed to ignore his requests to humanize the story's villains. In his opinion the novel painted them as cardboard monsters. With only a partial draft completed, Uris left the film.
Alfred Hitchcock shot three versions with completely different endings. All are included in the laserdisc reissue.
Karin Dor dubbed her own voice in the German Version of the Film.
Leon Uris wrote the first draft of the screenplay, but Alfred Hitchcock declared it unshootable at the last minute and called in Samuel A. Taylor (writer of Vertigo) to rewrite it from scratch. Some scenes were written just hours before they were shot.
According to Alfred Hitchcock, this was another of his experimental movies. In addition to the dialogue, the plot is revealed through the use of colors, predominantly red, yellow and white. He admits that this did not work out.
According to Donald Spoto's book "The Art of Alfred Hitchcock: Fifty Years Of His Motion Pictures", Universal Pictures executives forced this project on Alfred Hitchcock.
After Leon Uris left the film, Alfred Hitchcock asked Arthur Laurents if he was interested in working with Hitchcock on the script of Topaz. But Arthur Laurents refused. So Hitchcock called Samuel A. Taylor to work on the script. One of the difficulties Hitchcock and Samuel Taylor faced was they didn't have enough time to work on the script. According to the book "The A-Z of Hitchcock", Samuel Taylor had to continue writing throughout the shooting.
Knowing that he had no ear for music, Alfred Hitchcock didn't even bother listening to Maurice Jarre's completed score for the film, slotting it onto the images without a quibble.
The opening credits lists the most comprehensive cast - all 25 members; the end credits list only 11 of those members with character names. IMDb policy, therefore, requires the opening cast list to be used.
The shop that the Kusenovs visit just before their defection is Den Permanente, a permanent exhibition of Danish Arts and Crafts. It was founded in 1931 as a cooperative by some Danish artists and craftsmen.
This film was Alfred Hitchcock's biggest failure. It cost approximately $4,000,000 to make and received only $1,000,000 at the box office.
This was the second appearance of Karin Dor in an English Language Feature but the first time her own voice was kept in the original version. She has appeared in You Only Live Twice two years before but was dubbed by another English actress then.
Was reportedly one of Alfred Hitchcock's most unhappy directing jobs.
Alfred Hitchcock:
about 30 minutes in at the airport getting out of a wheelchair.