Recorded together but released a year apart, Kid A (2000) and Amnesiac (2001) marked a huge departure from the increasingly baroque guitar-led anthems of Radiohead’s first three albums. The broadening of their palette to embrace Warp-influenced electronica, free jazz and krautrock abstractions initially baffled many (the Guardian awarded Kid A two stars, while Melody Maker’s reviewer was reduced to describing it as “post-bollocks”), but get past the glitchiness and the occasional moments of discord, and here were songs as affecting and powerful as those on OK Computer, just framed somewhat differently. The change in direction clearly coincided with a particularly fertile period for the band, because this 20th-anniversary box features a bonus disc of unreleased contemporaneous material together with the two original albums. Perhaps unsurprisingly, nothing here eclipses Pyramid Song or Optimistic. Instead there are intriguing alternate versions (including yet another iteration of Morning Bell, this time a lullaby-like instrumental take), half-finished sketches, the gorgeous string arrangement of How to Disappear Completely in isolation, foreshadowing Jonny Greenwood’s Oscar-nominated score for Phantom Thread – and two previously unreleased songs. The attractively loose-limbed If You Say the Word failed to make the cut at the time because its mellow aesthetic didn’t fit; the dread-filled Follow Me Around (a version of which appeared as far back as the 1998 documentary Meeting People Is Easy) is just Thom Yorke and acoustic guitar, and is decidedly uncomfortable listening. Together they comprise a fascinating companion piece for two classic albums.