"Oh Well" is a song first recorded by Fleetwood Mac in 1969, composed by vocalist and lead guitarist Peter Green. It first appeared as a Fleetwood Mac single in various countries in 1969 and subsequently appeared on revised versions of that year's Then Play On album and the Greatest Hits album in 1971. It later featured on the 1992 boxed set 25 Years – The Chain, and on the 2002 compilation album The Best of Peter Green's Fleetwood Mac. A live version of the song was included on the 1998 compilation The Vaudeville Years.

"Oh Well" was composed in two parts, "Part 1" being a fast electric blues song with vocals (lasting 2:19), "Part 2" being an entirely different instrumental piece with a classical influence (lasting 5:39). The original 1969 single features the first minute of "Part 2" as a fade-out coda to the A-side and then "Part 2" begins again on the B-side. Later releases varied in length. At concerts, only the first part was played, and live versions of the song have been released on many Fleetwood Mac live albums throughout their career such as Live and Live at the BBC, as well on the B-sides of singles. After Green's departure, the song was sung by various other members, including Bob Welch, Lindsey Buckingham, Rick Vito and Billy Burnette.

The first part of the song features a fast blues guitar riff played by Green, joined subsequently by Danny Kirwan and bassist John McVie, before a musical silence, punctuated only by Mick Fleetwood's cowbell percussion. Green sings a brief verse with no musical accompaniment, before the riff begins again and Kirwan takes a solo. Another silence precedes a second verse, and a replay of the riff. Where the second part follows, there is a brief pause before Green's sombre, Spanish-style acoustic guitar and low electric guitar, leading to further instrumental passages of recorder, cello and piano, the latter played by Jeremy Spencer. This was Spencer's only contribution to the song, as he was absent from the recording of "Part 1", and Green played all the other instruments heard during "Part 2".

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