Albums of the decade No 2: Radiohead - Kid A

If Achtung Baby was the sound of U2 chopping down The Joshua Tree, Kid A saw Radiohead ripping the wires from OK Computer, setting fire to the motherboard and throwing the wreckage from a tenth floor window. The sound of a stadium-rock band dissolving and regrouping into something considerably less well-defined, the bold steps made on their fourth album liberated Radiohead, enabling them to approach each subsequent record free from the shackles of preconceptions.

Depending on your sensibilities, Kid A was the moment when Radiohead became either wilfully contrary and insufferably worthy (no single, no video, strictly no fun) or just about the only big band that mattered. Having suffered an allergic reaction to the conventions – both musical and personal – of stardom, they almost split up after OK Computer but instead settled on a "change everything" ethos, largely dispensing with guitars in favour of skittish rhythm and an electronic sound palette inspired by krautrock, free jazz and the more abstract end of hip-hop.

Released in October 2000, Kid A wrestled with key post-millennial themes: the application of technology, information overload, identity and alienation. Doggedly anti-corporate and often stubbornly anti-melodic, it sometimes seemed less a collection of songs than a prolonged experiment in sound and possibility. There were moments when the band second-guessed their own instincts to a ludicrously leftfield degree, but also moments of profound beauty and deep emotion. Motion Picture Soundtrack had the ache of a long goodbye; How to Disappear Completely sounded like a letter from a desperate man confronting the corrosive effects of fame. Like much of the album, the scrambled paranoia of Idioteque – "Ice age coming ... we're not scaremongering" – was a jittery premonition of the troubled, disconnected, overloaded decade to come. The sound of today, in other words, a decade early.

Buy this Sunday's Observer for the full top 50 countdown, plus an interview with the winner