This is, as far as I can remember, my first foray into spy novels, and it's a pretty good one--Graham Greene said it was "the best spy story I have ever read." Alec Leamas, a British agent in early Cold War Berlin, is called back to London by Control after his last double agent is killed. Instead of being dismissed, he is given a rather dangerous assignment: play the part of a disgraced agent, a defector, as part of a plot to bring down Mundt, an assassin for the Abteilung, the East German Secret Service.
The novel is of course suspenseful and entertaining, but it also seemed somewhat more literary than I had expected. It's well written and carefully plotted, and Leamas is more of an anti-hero, hard drinking and disillusioned, than some kind of slick action hero. Good stuff all around.