A much maligned Hitchcock film, and there are reasons for this. It's too long, and very slow moving, the plot is incomprehensible at times, and the lead actor--Frederick Stafford--is deadly dull. However, despite all this, I think the movie is pretty good. First of all, compositionally it is truly amazing--the camera work and the framing are some of Hitchcock's best. And structurally the film is brilliant, broken into three fairly distinct segments (they could be called Copenhagen/New York, Cuba, Paris), and weaved through these segments is the use of color as symbolism (an experiment Hitchcock believed was a mistake). It reminds me in a way of Traffic, with its many character threads and leaping locations.
All in all, much better than I'd hoped. I'll probably watch it again some day, if for no other reason than to see Karin Dor again, the German actress who plays Cuban spy Juanita in the film (the best performance in the film by far).