5 Fingers

This film is far from forgotten. Fans of James Mason and director Joseph L. Mankiewicz know it well. It's one of the most intelligent spy thrillers ever thanks to an Oscar-winning screenplay by Michael Wilson ("Bridge on the River Kwai," "Lawrence of Arabia," and the original "Planet of the Apes"). It also has a score by Bernard Herrmann. What else do you need? Other comments here have told what the plot is, so all I'll say is I envy you if haven't seen it yet and plan to. It's gripping and enjoyable all the way, and wonderfully ironic.