The Art of Documentary?

I guess it's only appropriate that the week when this year's Oscar documentary shortlist was released and heavily criticized is the week when I finally got to catch up with the Academy's best doc of 2003. The Fog of War is an undeniably intriguing look at Robert McNamara and his role in WWII and the Vietnam War. Was it the best documentary of the year? Possibly. I personally preferred Spellbound, but that matter is entirely up for debate. What I want to know is: what makes a good documentary?

As I read AJ Schnack's passionate attack on the Academy's choices, I was forced to confront my own knowledge (or lack thereof) concerning the art of documentary filmmaking. I barely know any history of documentary and the Academy, but Schanack, who is at this point the de facto online source for documentary info, talks about the 90s as a dark era when the only docs even nominated had to be about the Holocaust. Of course, I'm exaggerating Schnack's thoughts, but his recent post talks about a return to the Bad Old Days, which of course indicates that the Old Days were indeed bad. And then there's the matter of Errol Morris and Michael Moore.

These men were, until 2002, routinely overlooked by the Academy for their "groundbreaking" documentaries. I put quotes around groundbreaking because I haven't seen a Morris film besides The Fog of War, and even if I had, I wouldn't know what makes it groundbreaking. I've seen multiple people talk about Morris' aesthetics as new and original for documentary, but there has never been any proof. Is there a book on Morris or Moore that could help explain what makes these men such legends in their field? Are there any essays that help explain their place in documentary history and their accomplishments? Of course I plan to see Roger and Me and The Thin Blue Line, but until I get that chance, I would like to know where I can inform myself and be able to participate in any discussions on docs. Any help would be greatly appreciated.