I love the art of letter-writing--it really is an art, and a lost one, and I miss the idea of it--and nothing captures it better than reading a great collection of letters, like the letters from Normal Mailer collected in last week's New Yorker.
There are loads of quotable passages, but I can't help but quote this letter to Don Delillo, the last sentence of which is just... wow:
What a terrific book [Libra]. I have to tell you that I read it against the grain. I've got an awfully long novel going on the CIA, and of course it overlapped just enough that I kept saying, "this son of a bitch is playing my music," but I was impressed, damned impressed, which I very rarely am. I think we keep ourselves writing by allowing the core of our vanity never to be scratched if we can help it, but I didn't get away scot-free this time.