Could it be The Man Without a Name?
I don’t think I have read that, pretty sure that’s not it. I kinda think the author was a woman, and I don’t think the title would have referred to post-D-Day intelligence activity specifically. I believe that I have referenced that book in FR in the past, but even that doesn’t narrow down the search much because I have posted a lot over the years, now coming closer to 20, that I have been on board here.I keep a “cheat sheet” of links, including a number to Amazon Books web site, that I often use to avoid reinventing the wheel. But I looked thru that, and didn’t spot it.
“Could it be The Man Without a Name?”
Wasn’t that about creating a ruse that the allies were going to invade Greece with the intention of delaying the start of Operation Barbarossa by making the Germans shore up their southern flank?