Hitchcock filmed each scene in ten-minute segments (the length of a reel of film at the time), each segment continuously panning from character to character in real time. Each ten-minute segment ends by panning against or zooming into an object (a man's jacket, or the back of a piece of furniture, for example) or by having an actor move in front of the camera, blocking the entire screen; each scene after that starts a static shot of that same object. (This technique has been used frequently since to "hide" edits, for instance in the Eagle-Eye Cherry music video "Save Tonight," and also in Erin Brockovich: Julia Roberts appears to get into a car, drive down the street, and get hit by another car, but in fact the camera lingers behind on the road after she leaves, and at that point Steven Soderbergh cuts).
The film features Jimmy Stewart as a professor who espouses theories of moral superiority, from whom the killers take inspiration.