I've just finished reading Le Carré's book The Looking Glass War, and what a strange, and ultimately depressing, book - but a rollercoaster well worth reading.
The main central part of the book made me wonder what the (apparent) bunch of wannabe spies were doing - all of which is revealed as the book reaches it's conclusion.
I don't think it's a spoiler to say it's a book of multilayered betrayal and a warning against living today on past glories.