EL&P's marriage of art pop and prog reaches a climax on 1973's Brain Salad Surgery. Reminiscent of Frank Zappa's innovative production work, the album is a massive sound collage, one that ventures from William Blake poetry ("Jerusalem") to manic baroque electronica ("Toccata") to sci-fi dancehall ("Benny the Bouncer"). The sci-fi vibes only intensify during the closing "Karn Evil 9" suite, the bulk of which features Keith Emerson's mind-bending Moog work front and center. On the fiery "2nd Impression" he even gets his synths to sound like robotic kettle drums; this is super cool, of course.