Trivia

Since the filming times were so long, everybody on the set tried their best to avoid any mistakes. At one point in the movie, during the first take scene, the camera dolly accidentally ran over and broke a cameraman's foot, but to keep filming, he was gagged and dragged off the soundstage. Another time, a woman puts her glass down but misses the table. A stagehand had to rush up and catch it before the glass hit the ground. Both parts are used in the final cut.

The theatrical trailer features footage shot specifically for the advertisement that takes place before the beginning of the movie. David (the victim) sits on a park bench and speaks with Janet before leaving to meet Brandon and Phillip. James Stewart narrates the sequence, noting that's the last time Janet and the audience would see him alive.

Sir Alfred Hitchcock's first color movie.

This movie was unavailable for three decades because its rights (together with four other movies of the same period) were bought back by Sir Alfred Hitchcock and left as part of his legacy to his daughter Patricia Hitchcock. They've been known for a long time as the infamous "five lost Hitchcocks" amongst movie buffs, and were re-released in theaters around 1984 after a thirty-year absence. The others are Rear Window (1954), The Man Who Knew Too Much (1956), The Trouble with Harry (1955), and Vertigo (1958).

This was the only movie James Stewart made with Sir Alfred Hitchcock that he did not like. Stewart later admitted he felt he was miscast as the professor (he makes his first entrance twenty-eight minutes into the movie).

Alfred Hitchcock: appears, though barely if at all recognizable, walking down the street during the opening credits at around 2 mins as one of two pedestrians walking up a sidewalk holding a newspaper. The neon sign advertises "Reduco", the same fictional weight-loss product that Hitchcock advertised in his famous newspaper ad cameo in Lifeboat (1944).

Alfred Hitchcock: [Identifying with the killer] Throughout the movie, Brandon and Philip are at risk of exposure.