The Man Between by Charles Cumming
Suggested to me by an afficionada of the spy genre, I must admit that this book didn’t impress me at the start; the basis of the story seemed too improbable. But as I got further in it won me over and I ended up binge-reading the last two-thirds. A writer of spy fiction gets sucked into real-life black ops where no-one is ever quite who they seem to be, A good read.