This has always been one of my favorite Bob Dylan songs, though I didn't know until recently that it never actually appeared on an album.
Growing up, my parents had it on Greatest Hits Vol. I, so that was really my only exposure to it. I guess I'd just always assumed that it was from Highway 61 or Blonde on Blonde or some other classic album that I don't own. The only Dylan records I've ever had are Another Side of Bob Dylan and Bringing it all back Home. Well, those and Greatest Hits volumes I and II.
Undeniably one of the greatest (if not the greatest) lyricists ever, this one always stood out to me as one of the harshest things I'd ever heard.
Upon further review, it appears that it's about some unfortunate soul who didn't support Dylan's move to electric from the ranks of the acoustic folkies. But man does this guy get the proverbial dressing down. If you've ever seen Don't Look Back, the D.A. Pennebaker documentary covering Dylan's 1965 UK Tour, the sardonic wit of Positively 4th Street no longer would have surprised you. Some of the answers that Dylan has in the film for the British press are absolutely priceless. I haven't seen it in a while, maybe I should revisit it.