"Theme for an Imaginary Western" is a song written by Jack Bruce and Pete Brown.
It has been performed by many artists, including Mountain, Jack Bruce, Leslie West, Colosseum, Greenslade, DC3 and Johan Asherton.
The lyrics by Pete Brown are mentioned in Brown's autobiography "White Rooms and Imaginary Westerns" (ISBN 978-1906779207) as being in reference to Bruce's erstwhile bandmates Dick Heckstall-Smith and Graham Bond of The Graham Bond Organisation.
Mountain bassist/vocalist Felix Pappalardi, who sang the song with Mountain, had helped produce Bruce's album and brought the song to guitarist/vocalist Leslie West's attention for their album.
[3] The song was also covered by English jazz rock band Colosseum on their 1970 album Daughter of Time.