"Unknown Song" is an instrumental track written and recorded by the British

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 psychedelic rock

Psychedelic rock

Psychedelic rock is a style of rock music that is inspired or influenced by psychedelic culture and attempts to replicate and enhance the mind-altering experiences of psychedelic drugs. It emerged during the mid 1960s among folk rock and blues rock bands in United States and the United Kingdom...

 group Pink Floyd

Pink Floyd

Pink Floyd were an English rock band that achieved worldwide success with their progressive and psychedelic rock music. Their work is marked by the use of philosophical lyrics, sonic experimentation, innovative album art, and elaborate live shows. Pink Floyd are one of the most commercially...

. It has been released only on a bonus disc included in the 1997 re-release of the soundtrack

Zabriskie Point (album)

Zabriskie Point is a soundtrack album to the Michelangelo Antonioni film of the same name. It was originally released in January 1970 and is composed of songs from various artists. A 1997 re-release includes four bonus tracks each from Jerry Garcia and Pink Floyd that were used in the film, but not...

 to Michelangelo Antonioni

Michelangelo Antonioni

Michelangelo Antonioni, Cavaliere di Gran Croce OMRI was an Italian modernist film director, screenwriter, editor and short story writer.- Personal life :...

's movie Zabriskie Point

Zabriskie Point (film)

Zabriskie Point is a 1970 film by Italian director Michelangelo Antonioni, widely noted at the time for its setting in the late 1960s counterculture of the United States...

. The track is simple and consists of melodies that were used later; the riff that starts to play at 1:54 is a faster tempo version of the "Funky Dung" section of "Atom Heart Mother

Atom Heart Mother (suite)

"Atom Heart Mother" is a six-part suite by progressive rock band Pink Floyd, composed by all members of the band and Ron Geesin. It appeared on the Atom Heart Mother album in 1970, taking up the whole first side of the original vinyl record...

". The main melody played by acoustic 12-string guitar throughout the song is somewhat typical to the style band had later – "A Pillow of Winds

A Pillow of Winds

"A Pillow of Winds" is the second track from Pink Floyd's 1971 album Meddle.According to the 1996 Pink Floyd history book by Cliff Jones, the band felt that "One of These Days" was such a powerful track that they needed to bring everyone down with something gentle. The song is a soft acoustic...

" or even "Brain Damage

Brain Damage (song)

"Brain Damage" is the ninth track from British progressive rock band Pink Floyd's 1973 album, The Dark Side of the Moon. It was sung by Roger Waters. David Gilmour took over as lead vocalist when the band performed it live on the band's 1994 tour...

" can be heard as followers of the song's melodies.

"Unknown Song" is sometimes called "Rain in the Country" or "Country Rain" on bootleg recording

Bootleg recording

A bootleg recording is an audio or video recording of a performance that was not officially released by the artist or under other legal authority. The process of making and distributing such recordings is known as bootlegging...

s. A similar piece entitled "Baby Blue Shuffle in D Major" appeared in a December 2, 1968 BBC

BBC

The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

 radio broadcast and shared melodies with part one of "The Narrow Way

The Narrow Way

"The Narrow Way" is a section on the studio half of Pink Floyd's fourth album Ummagumma. It was written and performed by David Gilmour and is divided into three parts...

" from Ummagumma

Ummagumma

Ummagumma is a double album by English progressive rock band Pink Floyd, released in 1969 by Harvest and EMI in the United Kingdom and Harvest and Capitol in the United States...

, but it may have been rather a different – or even the same – take of "Unknown Song".