The Amazing Mr. X, also known as The Spiritualist, is a 1948 American horror thriller film noir directed by Bernard Vorhaus with cinematography by John Alton. The film tells the story of a phony spiritualist racket. The film is prominently featured in Alton's book on cinematography Painting with Light (1949).

John Alton, born Johann Jacob Altmann, in Sopron, Kingdom of Hungary, was an American cinematographer of Hungarian-German origin. Alton photographed some of the most famous films noir of the classic period and won an Academy Award for the cinematography of An American in Paris (1951), becoming the first Hungarian-born person to do so in the cinematography category.