The job was the betrayal
Alec Leamas is burned out, and Control offers him one more operation. The cover is that he has fallen apart. The drink, the bad job, the money trouble: some of it is acted and some of it is just what is left of him. I have seen the story summarized as a twist about who was betraying whom. The twist is real, and it is not what I kept. What I kept is how little the people who planned it need Leamas to be told the truth, and how completely Liz is treated as a piece that makes the rest of the board look innocent.
Le Carré writes the Cold War here as an office that has learned to call its cruelties a method. Mundt, Fiedler, Control: they are not the same kind of man, and the book does not pretend the other side is cleaner. It also does not offer Leamas a professional satisfaction at the end. Competence is the trap. He is good enough to see the shape of the operation only when he is already inside it, standing where someone else decided he would stand.
The last pages are short. I will not describe them. I read them twice, the second time to see whether the book flinches. It does not. Afterwards the earlier scenes, the ones that felt like atmosphere, looked like preparation. That is a nasty gift for a novel to give you, and it is why this one is still the spy novel I would hand to someone who thinks the genre is about cleverness.