I mean, of course it's a masterpiece. Who else in the history of pop/rock/whatever has stripped away their defining musical characteristics and delivered their greatest album? Answer - no-one. Kid A's genius is how it placed the unease at the core of Radiohead's music front and centre, refusing to sugar-coat it with sparkling guitars and vocal harmonies. Instead, they want us to experience the audio turmoil, moving the weird noise down the stairs at 3am to middle of the sound picture, rather than hiding it beneath the surface, letting the loop that won't get out of your head sit for a while, wandering away into dreamlike errands before warping into a classic anxiety nightmare. It's a surreal, disquieting album which has proved thoroughly prescient.