During the run-up to the release of Radiohead’s 2000 electronic opus Kid A, the band members often spoke about breaking up. It was, in part, a hypothetical consideration, one that preceded the album’s recording sessions: If the group’s heralded 1997 release OK Computer was such a masterpiece, why bother trying to top it? But it was also an acknowledgement of the intra-band tension involved in the making of Kid A. That album—which found Radiohead pushing past its guitar-rock sound—had led to shouting matches and tirades, power plays and pity parties. Could the bandmates actually endure making a follow-up? But as Radiohead toured in support of Kid A—which at one point had been conceived as a double album—the members began listening to the dozens of songs and sketches that didn’t make the cut the first time around. Which is why, just seven months after Kid A’s release, Radiohead returned with 2001’s Amnesiac—an album Thom Yorke described as “our secret weapon against all the weirdness going on.” It was a surprisingly cohesive companion that at once felt more esoteric and accessible than its predecessor. And Amnesiac proved that the electronic explorations and the fragmented lyrical codex of Kid A weren’t a fluke: This was now Radiohead, at a new vanguard of rock. Informed by Charles Mingus, “Pyramid Song” is one of the prettiest songs in Radiohead’s catalog, its meaty piano chords and ominous electronic tide lifting Yorke’s falsetto croon. And though it’s a polemic against Tony Blair and politicians like him, “You and Whose Army?” is an exquisite drift, anchored by Colin Greenwood’s perfect bassline. “Life in a Glasshouse,” meanwhile, unfurls over the jazz-band sighs of British trumpeter Humphrey Lyttelton. It’s a song you could slip into a family holiday playlist—so long as the volume remained low enough to hide its little symphony of dissonance. Amnesiac also proved just how far the group had ventured into electronics and abstraction. The askance percussion samples of “Packt Like Sardines in a Crushd Tin Box” dart around its dance-floor rhythm like a tease, with Yorke riding the beat with stunning R&B aplomb. And the band wanders into electro-acoustic territory for “Hunting Bears,” which features a pensive spaghetti-western guitar slowly sinking into itself. Meanwhile, “Pulk/Pull Revolving Doors” remains one of the most aggressive Radiohead cuts, its mix of battering-ram arrhythmia, prepared piano strikes, and static loops clawing at Yorke’s warped voice like the track is an existential battle for space. What Amnesiac lacks in clear narrative it makes up for in breadth—and in its ability to suggest the many directions in which Radiohead might still move.