Not a bad book but not exactly riveting.The spies are interesting with a couple of WW II stories and the rest in the Cold War.They are short(good) but sometimes are involved with code names.Not sure if the details are correct now or whether more files have been opened to reveal more secrets.The author does challenge other author’s “facts” as being wrong eg accepting Gestapo reports which in fact were part of the deception scheme.Much of the account of Greville Wynn’s actions is explaining the falsities in his books.Anyway useful but,as with spies, still mysterious.