is possibly the best Cold War spy thriller for me. I stopped reading le Carre when his later novels became bloated when he got literary pretensions (the tedious George Smiley).

An early Graham Greene novel , The Confidential Agent is pretty good, and The Third Man, a novella based on his film script.

Not strictly a spy thriller, The Small Back Room by Nigel Balchin is a good WWII read. The bomb disposal hero has a tin foot. Made into an excellent film by the Archers.