Was just going to recommend, hornets flight, but he wasn't a spy, just a teen boy needing to warn allies of first radar in Denmark. I also LOVE Follets books, has a gread one about French resistance in ww2 jackdaws also coldwar-space race code to zero, also a book about days leading into Russian involvement in ww1 man from st Petersburg , in addition some of my faves, on wings of eagles, not war book but great true story of hostage rescue in Iran by Ross Perot (a great Texan), and he wrote another about the first trans Atlantic passenger flight, but the name has just escaped me, his subject matter is all over the place, I also highly recommend anything Grisham, but that's just me, we have a small up and comming library in our house and I have also been reading lots of presidential bios, GB 41 has one about his time shot down and as POW THAT'S GREAT, McCain book is good too, Stewart woods books are also decent, along with Jeffery archer, also I don't know if your familiar with Larry McMurtry, another great Texan , (lonesome dove) his books ate great too
Just finished the good German by Joseph kanon it was pretty good