Astral Weeks is part of the standard classic rock canon. At least it used to be. But it's really not even a rock album: it's jazzy folk with other stuff thrown in, unique sounding and very different from anything Morrison did before or after. I think it's been hugely influential -- listen to "Madame George" and it's not hard to picture Tom Waits singing it or Bruce Springsteen stealing a riff. (When I first heard Neutral Milk Hotel I thought of this album as well). I think it's too bad it gets overlooked today. It's not easy listening, Morrison gets in a groove in spots and doesn't seem to worry about whether he's actually carrying his tune. But patience will be rewarded.