Pink Floyd's fourth album was a double-LP package, with one record devoted to live recordings of four songs and the other to individual studio projects by each of the four principals at the time (David Gilmour, Nick Mason, Roger Waters, and Richard Wright). I've never much connected with the studio projects, which seem more aimless and empty ego-driven exercises of some kind. The live album is open to criticism too—the songs are simplistic, the playing rudimentary, and the recording not particularly inspired. Nonetheless, the performances mark a kind of fantasized rock concert ideal that appealed to me then, and still appeals to me now, and not as nostalgia. What I mostly like are the simplistic songs and the rudimentary playing, almost perfectly unself-consciously capturing the essence of a late-'60s rock concert, at least as I understand them from the stories. There's a lot of play with dynamics on all this music, as every song stretches out eight minutes and more. They bring it down to soft bass notes, softly brushed guitar chords, casual keyboard notes or chords, and drums barely tapped and poked at. Then it becomes loud again, with sound arriving like a tidal wave. In many ways they are inventing a kind of rock staple. The ideas are not yet fully developed but the excitement of their discovery makes it irrelevant. It's easy to imagine a crowd listening to this sitting on a filthy floor and zonked out of their minds. Among other things, it's excellent stoner fare. There is a drum solo, of course. Syd Barrett's "Astronomy Domine" gets the honors for kicking it off, but my favorite of the four songs is Roger Waters's spooky "Set the Controls for the Heart of the Sun," a strange and doomy ride aboard a spaceship with astronauts who sound hypnotized. Their mission: see title. (Maybe this is post-HAL fallout from 2001?) Another song with a descriptive title, "Careful With That Axe, Eugene" is a collaboration of all four of them. It reminds again of Pink Floyd's flirtations with certain tropes of horror cinema, also seen, for example, two years later in Meddle's opening track, "One of These Days" (you have to pick it out of the production but the monster voice there is saying "One of these days I'm going to cut you into little pieces"). I'm assuming this is more of Roger Waters's lifelong anger management sorting-out? At any rate, "Careful With That Axe, Eugene" only has the title phrase and some uncomfortable screaming to explain itself, which is no explanation at all. Mostly it's a moody arguably overlong guitar showcase. I am not making that argument, though I could do without the screaming. At worst, the set is merely quaint, lightweight, and silly. You bet a song like "Set the Controls for the Heart of the Sun" is easy to mock. I swear it works, however. I've been listening to it all my life.