"Interstellar Overdrive" was Pink Floyd's first major space jam and perhaps the song most representative of what you might have heard them play in concert while Syd Barrett was in the band, though it wasn't too representative of the songs they recorded when he was in the group. Like the Paul Butterfield Blues Band's slightly earlier "East West," "Interstellar Overdrive" was one of the very first of the long, psychedelic instrumental improvisations recorded by a rock band, running about ten minutes when it appeared on their first album in 1967. The main hook of the piece is a crunching, zigzagging descending riff played with vicious authority on Syd Barrett's guitar. As the rest of the band joins in, the riff eventually fades out of the picture, allowing space for Middle Eastern-like wanderings by organist Rick Wright. The song becomes almost structureless and tempo-less during its strangest sections, punctuated by strange guitar/electronic noises that simulate the beeps of interstellar spacecraft quite well. Eventually, however, the band circulates back to the main grinding theme, stated again a few times at the end of the song with slower, more deliberate intensity, until it crashes to a halt. This riff, incidentally, originated when early Pink Floyd manager Peter Jenner tried to hum Syd Barrett the main riff of a Love song he couldn't remember the name of (probably from Love's cover of "My Little Red Book," possibly "Stephanie Knows Who"). Barrett followed Jenner's humming with his guitar and used it as the basis for the principal riff of "Interstellar Overdrive." The studio recording on The Piper at the Gates of Dawn is the one that most listeners are most familiar with, yet several other versions exist, from both the studio and the stage. There is an earlier, 16-minute version the band recorded for the soundtrack of Tonite Let's All Make Love in London, which is actually superior and more kinetic in its early section, though more tedious and drawn-out as a whole. There are also some live recordings from bootlegs, with both the Barrett and David Gilmour lineups, that show the band often improvised upon and changed the arrangement; one BBC broadcast, for example, is arguably superior to the studio version, introducing a wholly new middle section in which the keys dramatically rise and the guitars are scraped for particularly demonic electronic effects. The best-known of the few cover versions of "Interstellar Overdrive" are probably the ones by Pearl Jam, with several different ones showing up on their innumerable live releases.