The Spies overlaps most of the over categories, esp. The Nazis. The best of this lot is John Le Carre, no question, and not much more really to say. Even at his worst, Absolute Friends for example, he's a good read, and his best - Smiley, Tinker Tailor Soldier Spy, A Perfect Spy - are mesmerizing. He's considered by many to be the intellectual heir of Eric Ambler, and it is not hard to see why, although Ambler likes to deal more regularly in the theme of the unknowing person caught up in dark events beyond his (always) control. Didn't like that new Olen Steinhauer, The Tourist, much at all (unrelentingly depressing and hard to understand why), so I haven't pursued those, which is too bad because his earlier series was great.
I think I read fewer spy works these days, having moved along more to crime itself.