Random Harvest is a novel written by James Hilton, first published in 1941. Like previous Hilton works, including Lost Horizon and Goodbye, Mr. Chips, the novel was immensely popular, placing second on The New York Times list of bestselling novels for the year.

The novel was successfully adapted into a film of the same name in 1942 under the direction of Mervyn LeRoy. Claudine West, George Froeschel and Arthur Wimperis adapted the novel for the screen, and received an Academy Award nomination for their work. Though the film departs from the novel's narrative in several significant ways, the novel's surprise ending, cleverly built on inferences drawn by the reader, would not work in a purely visual medium.

The film, unlike the novel, does not employ flashbacks. The narrative begins in 1918, when the patient simply called Smith is in the asylum. The viewer first encounters Paula in this context as his rescuer, and so is well aware of her identity throughout the film.

Rainier meets Paula for the second time some time after 1920, having recovered his original memories, but having lost the memory of his years as Smith, her husband. She identifies herself to him as Margaret Hansen, and becomes his trusted private secretary, later entering into a non-romantic, platonic marriage with him. Her motives and anxieties are revealed to the audience through discussions with Dr. Jonathan Benet, Smith's psychiatrist from the asylum, a character original to the film. He cautions her that she must not reveal her true identity to Rainier, that he must recover his memories, if he's going to, spontaneously.

Thus, at the end of the film, it is only to Charles Rainier / Smithy that Paula's true identity is revealed, and there is never any uncertainty that she is his lost love.

Kitty does not die in the film. Rainier's father is already deceased when he returns to Random Hall, and, after 1920 when he recovers his memories, no specific dates or historical events are given. We know only that enough years have passed for Kitty to graduate from university, and for Rainier to become ensconced in the business world.