"The Hardest Part" is a song by British rock band Coldplay. It was written by all four members of the band for their third album, X&Y. A piano-based ballad song, it begins with a piano melody, followed with electric guitar lines, that accompanies slow-tempo drumming. It was released on 3 April 2006 as the fourth single from X&Y. The song was released as a radio-only song on United Kingdom radio stations. It appeared on the United States Billboard Hot Adult Contemporary Tracks chart and peaked at number 37, making it Coldplay's first appearance on that chart and helping establish moderate success at AC radio for future singles like "Viva la Vida", "Paradise", and "Every Teardrop Is a Waterfall". "The Hardest Part" also charted in Australia, Italy and New Zealand.

The song was well received by critics. The track was complimented for its musical style. Regional singles were released in Canada, Europe, and Australia; a different version was released in Taiwan. Promo singles were released for the UK and US. The international version of the single was made available in the UK on 19 June 2006.

The previous single from X&Y, "Talk", was a tribute to the German band Kraftwerk; similarly, "The Hardest Part" was intended by Coldplay to acknowledge American band R.E.M. When asked why the song paid a tribute to R.E.M.'s lead singer, Michael Stipe, Chris Martin said: "I've lost all respect for fame, but I haven't lost all respect for respect. So the one great thing about being famous is that I get to meet people who I respect. Our relationship is akin to a dog and its master. I'll always look up to him." The band felt the track resembled R.E.M.'s 1991 single, "Losing My Religion". "The Hardest Part" was left out of the album track list when the band sent an early version of X&Y to their record label, Parlophone, but was included when the album was finalised.

...
Wikipedia