I would highly recommend Operation Mincemeat: How a Dead Man and a Bizarre Plan Fooled the Nazis and Assured an Allied Victory by Ben Macintyre. In fact, all of Macintyre's books on espionage are excellent.

There was also a pretty decent British film made in the '50s called The Man Who Never Was. Interestingly, I believe that much of the story was still classified at the time, so they had to leave a few things out.