I nominate The Secret Pilgrim. It's a sequence of vignettes about the Service as related by Smiley during a training session for new recruits. I remember finis

I nominate The Secret Pilgrim. It's a sequence of vignettes about the Service as related by Smiley during a training session for new recruits. I remember finishing the book, and feeling a profound sense of pity for the broken, fractured people working for MI6. A lot of Le Carre's stuff deals with the same themes -- but that was the first time I ever felt what the author was trying to put across. I've not read anything with similar impact since.