jonathan7 said, in another thread:
@Tyrphanax
Are there any sources for the OT EU prior to the Prequels, I've heard that Lucas contradicts a lot of the previous work, but unfortunately I've never seen/read the ideas that pre-dated the Prequels.
I'm not quite sure I know what you mean by sources... if you can find the old media, then that's the best source. The old Bantam novels and early Star Wars comics as well as the early sourcebooks and guides and whatnot. I have a well-read copy of the second edition of A Guide to the Star Wars Universe from 1994 which is all pre-PT info in blurb form. I know there was at least one edition later than the one I have, but I was pretty sure it had TPM content. There's also the Star Wars Encyclopedia from 1998 that's supposed to be pretty good. Wookieepedia will also generally give you some idea of retcons and stuff in the "Behind the Scenes" section in most articles.
The thing about Lucas contradicting the EU is, and what most people fail to realize, is that it's written with the understanding that if Lucas decides he wants to explore the section of the universe you wrote about, whatever he comes up with will trump your ideas.
This is most notably seen in the recent Clone Wars series on Cartoon Network. Helming the show is Dave Filoni, who is a pretty hardcore Star Wars nerd, which is great, because he likes to add some of the cooler EU points into the show. The thing is that Lucas has the final say on stuff, so you do end up with contradictory canon here and there. This is the main reason Karen Traviss ragequit the Star Wars universe, because Lucas wanted to do something different with the Mandalorians during the Clone Wars than she had (which could go either way for me right now, depending on what happens in the upcoming Season IV).
The nice thing about the process is that if Dave and his team are going to be exploring areas that have had content written about them already, they'll do their research on it (I'm sure they at least read the Wookieepedia entry if not the media involved) and they'll bring the pre-established ideas to Lucas' attention. Honestly, it seems like Lucas will generally okay the pre-established stuff, unless he feels very strongly about how he wants something done (and that's when you get pacifist Mandalorians and Dathomiri Zabraks).
As far as other things go, things like the PT contradicting OT EU, you have to be realistic about it. You can't very well expect Lucas and his team to put the production of their media on hold in order to go through and read all those books and comics and play all the video games and everything so that they have an idea of how to make this new media fit in with pre-established EU by some author from 1976 (and quite honestly, I don't think he should have to). Plus, he has at least two people who's job it is to retcon things and make sure everything fits together (sometimes pretty tenuously at best) into a fairly continual universe.
I hope that answers your questions!
The other thing about the EU, which I'll tack on here for the sake of answering the threads OP, is that I care (/skywalker), but you really have to pick and choose what you like and don't like to add to your personal canon. I've recently been going through the novels in SW chronological order and while there have been a few gems (like the Jedi Apprentice series, which makes TPM a better movie) and a few really awful books as well (I'm reading Cloak of Deception right now, which I so far do not like). You just gotta check it all out, add what you like to your canon and toss out what you don't.