It arrived in November 1971 with no name on it. Stung by critics who’d written them off, the band stripped the sleeve of everything: no title, no text, just four runic symbols, one chosen by each member, where the album’s name should be. Let the music argue for itself.

Most of it was cut at Headley Grange, a damp country house in Hampshire, using the Rolling Stones’ mobile studio parked out front. The rooms became instruments. A stairwell became a drum sound nobody could have planned in a proper studio.

Side one opens with the lurching riff of Black Dog and the rockabilly charge of Rock and Roll. Side two ends with When the Levee Breaks, all thunder and harmonica. And folded into the middle of the record is the eight-minute track that would outgrow the album, the band, and very nearly the rest of rock radio.