Brian Eno’s first two solo albums, 1974’s Here Come the Warm Jets and Taking Tiger Mountain By Strategy, weren’t too far from what he had been playing in Roxy Music just a couple years prior: catchy, glam-infused art rock from which unexpected details (a nonsense phrase, an eerie swatch of backmasking) sprouted as colourfully as the feathers in Eno’s boa. But by the next year’s Another Green World, the properties of his universe had gotten stranger. Straight lines turned soft and bendy; a coppery tarnish crept across his music’s once-bright hues. The shift is right there in the opening “Sky Saw”, whose murky swirl suggests a kind of aquatic dub funk, and “Over Fire Island”, in which Percy Jones’ fretless bass bubbles like magma beneath Eno’s dolefully drizzling synth lead. Eno had toyed with improvisation and stream-of-consciousness lyrics previously, but Another Green World marked a step further into the unknown: It was written and recorded on the spot, and he used his Oblique Strategies cards—an aleatory, free-form brainstorming aid—to point him toward new sounds, methods and tone colours. His invention of ambient music was still a few years away, but you can hear him edging toward it in the contemplative rhythms of “In Dark Trees”—which anticipates the globe-trotting explorations of 1981’s My Life in the Bush of Ghosts, with David Byrne—and “Sombre Reptiles”, featuring a slinky sound Eno termed “snake guitar”. But for all his experimenting, he didn’t ignore his pop instincts: “St. Elmo’s Fire” is as immediate and indelible a tune as he’s ever written, right down to its vividly surrealistic lyrics.