The writing is superb, as usual for the his author. I loved the satiric feeling of the scenes with the police, his old bosses at the Office, his ex-wife. The plot is complex, like "The Night Manager" and set in the post-Soviet era of the 1990's when the Russians were waging campaigns of ethnic cleansing against groups in the Caucasus. One interesting "prop" used was a hiding place for Tim: a "priest hole" concealed in a tower of the medieval church on his estate.
I "google-researched" the Caucasian Mountain countries of the Russian Federation; beautiful, brutal places with ancient stone towers and evocative landscapes.
The young woman, Emma, the love interest was the weakest link. Like the heroine in "The Night Manager": mystically beautiful but otherwise shallow and unworthy of having so much of the action in the novel directed at trying to "save" her. Meanwhile, this author able to create such deep and compelling characters out of "little grey middle-aged men" with bureaucratic jobs in spy agencies like Tim and like George Smiley (who does not appear in this novel).
Eventually, given enough time, I suppose I will read all the this author's fictional works. He is a wonderful writer who chose to work on espionage and crime thrillers.