Studio experts: What is "Mixing"?

Hey can any of you studio buffs answer a question for me? I know what producing is, I know what engineering is, but is "mixing" and what does it mean to "mix" a recording for release?
Keep in mind I'm not talking about club mixes and re-mixes and that crap, but mixing a recording, like for instance Dave says about DSOT "We didn't add anything we just mixed it." What does this mean?

Could you tell me what exactly producing is? I always wondered what exactly does a producer do?

and what is engineering? seriously i'm not kidding

I want to know that as well i have no idea what it all is. Is there an expert in here?

to mix is to go through all the tracks and find the levels you want. For example, you might want a lead guitar louder at one point than at another point. It's finding all the levels you want for all the instruments. This can also lead to panning (having the sound come out at lets say 70% right for example), post-recording effects (which I'm assuming that's what "we didn't add anything" was refering to)

check this site if you need other answers:
http://www.homerecording.com/glossary.html

I wish I was an expert...but will be...In college right now studying Sound Design...except I'm still taking freshman classes

Yeah, all that too..., but the most accurate definition would be something like: in the analog domain - summing up two or more channels/tracks of audio into a single track/channel/tape; in the digital domain - summing two or more digital audio signals into one digital audio signal (be it a real time stream or a file or whatever).

Well let's go to Roger for the answer:
"A record producer is someone who is in charge of a recording session, and to be in charge of a recording session you have to have a fairly extensive knowledge of what the equipment is about."
So you can relate it to the director of a film.

Engineering concerns the *technical* technical stuff, mechanical things that Alan Parsons or James Guthrie would do. Knowing all about sound systems, sound tools. Sort of like a computer geek who fixes/builds computers and knows all about which part does what, and what the band wants it to sound like. The producer on the other hand, has the input of what it should sound like, whereas the engineer usually just carries out orders (but probably not the guys I mentioned above).

P.S. I'm not an expert in here, so you may go to someone else for the answer.

A mate of mine owns a recording studio, and I just asked him, and he's said that you guys have more or less got it there.

To me:

Mixing: taking a multi-track source and combining it to stereo or mono; at the most basic playing a 4-track machine into a stereo tape recorder, and messing with the levels and panning. It gets more complicated than this, though.

Producer: a person in charge of a recording session; for musicans less than studio-smart, a translator to the engineer to get the sounds desired; a person who might direct the artist if the artist isn't musically or mentally inspired enough.

Engineer: basically, the person who runs the studio equipment when the producer might not want to.

A producer decides what direction a recording session takes. They are the ones who say "I think we need some more overdubs," or "that last take was the one we shall be using," or "the guitars need to sound more like this."

An engineer places microphones to achieve the desired effect, and operates other equipment (like delays and compressors) to get the right sound. The person doing the mixing then combines what has been recorded (possibly from multiple performances) into one finished product, either stereo or mono as Shane said, or nowadays, surround.

There might be other people in the studio too, like the tape machine operator or the instrument technicians or whatever. And sometimes one person takes on multiple roles, and sometimes multiple people do one role. But that's essentially how it works.

Incidentally, it turns out he was lying:

-From an interview with Buford Jones about the mixing of DSOT