Released as the second Amnesiac single, receiving more radio airplay than the band's other songs of the period. The song reached number 13 on the UK Singles Chart. It also topped the Canadian Singles Chart for 4 weeks.

The song was developed during the 18-month Kid A and Amnesiac sessions, and is known for having taken 373 days to record. According to Yorke, 'We just lost our nerve. It was so straight-ahead. We thought, We've gotta put that in the bin, its too straight. We couldn't possibly do anything that straight until we'd gone and been completely arse about face with everything else, in order to feel good about doing something straight like that. It took 373 days to be arse-about-face enough to realise it was alright the way it was'.

Although 'Knives Out' is not similar to Radiohead's earlier rock style as featured on The Bends (1995), it is usually noted as one of the most traditional guitar pop songs the band has done since 2000.

When guitarist Ed O'Brien played 'Knives Out' to Johnny Marr (The Smiths), Marr was touched when told that the track was heavily influenced by his former group. It was later covered by The Flaming Lips, on their 2003 EP, Fight Test EP. The song was also covered by classical pianist Christopher O'Riley on his album True Love Waits, and by jazz pianist/bandleader Brad Mehldau on his most recent album, Day is Done.