I nominate <i>The Secret Pilgrim</i>.<p>It&#x27;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.<p>A lot of Le Carre&#x27;s stuff deals with the same themes -- but that was the first time I ever <i>felt</i> what the author was trying to put across. I&#x27;ve not read anything with similar impact since.