There was a lot going on in the world of the Cocteau Twins as they made their sixth record. Birth, death, intra-band turmoil, substance abuse, and label tensions swirled around Elizabeth Fraser, Robin Guthrie, and Simon Raymonde, but the band which had formed in Scotland a decade earlier put it all into their masterpiece. The trio had refined their sound on 1988’s Blue Bell Knoll, with its hazy blend of sparse atmospherics and hypnotic pop melodies, and here they pushed everything further. Setting up base at Pete Townshend’s Eel Pie Studios in West London—rechristened September Sound by the trio—there was a sense of joy imbued in recording sessions prompted by the arrival of Fraser and Guthrie’s daughter Lucy Belle in September 1989, the month of her birth inspiring the new studio name. But there was discord, too—having a child hadn’t curbed Guthrie’s drug habit in the way his bandmates had hoped, while Raymonde was grieving the death of his father. Somehow, they turned the friction inside out when they worked on music. It’s not for nothing that the Cocteau Twins are saluted as the pioneers of what came to be known as dream pop. It’s all here in its most purified and exhilarating form, songs drenched in lush sonic textures where one track seems to drift into the next. You can hear what these instruments are but they don’t sound like themselves, guitars, bass, keyboards, and drums light and airy, coming in and out of focus, everything fluid and shapeshifting. The trick—and the reason the whole thing doesn’t simply float away into the ether—is how they combine that dynamic with a collection of irresistible pop hooks. Fraser’s at her ethereal, majestic best on the heady euphoria of “Cherry-Coloured Funk,” “Iceblink Luck,” and the title track. Added to the sense of motion are the mesmeric grooves underpinning everything, a rhythmic sway that propels “Fifty-Fifty Clown” and “Fotzepolitic” forward. It is the sound of a band hitting alchemical perfection. Unfortunately, that was about the only harmonious thing about them. Despite pinpointing Heaven or Las Vegas as his favorite ever release, their 4AD label boss and long-term ally Ivo Watts-Russell cut ties soon after release in September 1990, with relations between the two camps long since soured. Despite the turmoil, the ecstatic thrill of the music is what lives on. Cocteau Twins never again hit the heights of Heaven or Las Vegas, but leaving behind music this mind-blowing, perhaps they never needed to.