Guess the 1960s song lyrics #46

1968. This British band's producer contributed viola to this song. The song's cowriter was a poet who was a friend of the lead singer. They often collaborated. Jimi Hendrix was an inspiration for the song. The first draft of the lyrics were a depressed rambling about a hippie girl titled “Cinderella’s Last Goodnight.” It became a song about a colorless room he was staying in where he was able to get sober and come to terms with things.This major band was only together about 2 years.