The letters are from 1952, and some of them mention cartoons he was working on: he talks about the scoring of "Wild Over You", seeing the final assembled version of "Duck Dodgers," and pre-production on "My Little Duckaroo." There's also a look at WB's corporate freakout about the television menace (this being before Jack Warner became the first mogul to embrace television).
Other letters don't say much about the cartoon business and talk about personal matters, dieting, politics, movies he's seen (loves High Noon, dislikes that strangely unfunny Howard Hawks segment in O. Henry's Full House), and square dancing, which, as Michael Barrier has mentioned, was a big Termite Terrace obsession.
The thing that impressed and surprised me about these letters was that (and a commenter at Thad K's blog already made a similar point) Jones was essentially the same even when he wasn't trying to impress anyone. I always kind of assumed that, like many aging filmmakers, Jones's public persona -- in his interviews and his books -- was a bit of a put-on. (It certainly seemed of a piece with the self-indulgent turn his later films took.) But the Chuck Jones who emerges in these letters is pretty much Chuck Jones as he later presented himself to the public. That's not to say that these letters encompass all of Jones's personality, just that they reveal that as the best cartoon director in America (which is pretty much what he was in 1952) he was not substantially different from what he was when he wrote and talked about those golden years.
Even his descriptions of the characters, when he offers them, show that his view of (say) Daffy Duck was not a reductive idea he made up after the fact, but something he had in mind at the time:
I love Daffy dearly, he is so completely and foolishly human. I think he serves to accent all the human frailties and vanities and conceits and is funny doing it.
(Oct. 1, 1952)
Letters are being posted when they have a chance. I'll be interested to see if there are any letters where he sets out the "rules" for the Road Runner/Coyote series. I used to think it was something he made up after the fact; now I'm not so sure.