All Dylan fans, a club to which I am only a very recent convert, must check out Greg Sandow's most excellent article on Dylan, here.
Sandow is the classical music critic for The Wall Street Journal, and also has just started writing a superb blog on that very same subject for ArtsJournal.com.
The Dylan piece is great precisely because of Sandow's background as a classical critic; indeed, the piece is primarily about the odd dissonances Dylan, particularly early Dylan, employed, and why they work. It may sound dauntlessly technical, but my knowledge of theory is tenuous at best, and I loved it. If you need another reason to check it out, the following sentence should do it:
To represent Dylan's harmony in any kind of formal musical analysis, I'd have to write out the chords and then crumple the paper, spill coffee on it, carry it around in my pocket for a couple of weeks, wipe my mouth on it, and sleep with it..