George Harrison's band for many of the soundtrack recordings was the Remo Four, who were contemporaries of The Beatles from Liverpool. Learning they were about to break up, Harrison hired them for one last project. Other musicians on the non-Indian tracks (recorded at De Lane Lea Studios) included John Barham, Eric Clapton, Ringo Starr, Peter Tork (playing a five-string banjo Paul McCartney lent him) and Harrison himself, mostly under pseudonyms.
Star Jack MacGowran was referred for the role of Oscar by writer Gérard Brach and director Roman Polanski, during production of The Fearless Vampire Killers in which he also played an eccentric professor.
The Indian portions of the soundtrack were recorded (live to two-track stereo) at EMI's studio in Bombay, in January 1968, and included Ashish Khan on sarod, and other musicians George Harrison knew through Ravi Shankar. The same sessions produced the backing track for "The Inner Light", which became the B-side of "Lady Madonna" - issued while The Beatles studied in India with Maharishi Mahesh Yogi, later the same year.
The movie gained an undeserved reputation for "never having been shown", because while it did have a Cannes premiere (winning an award), and other selected art-house showings in the late 1960s, no distribution deal was ever worked out, and the movie never had a wide release. (A low-quality print finally found its way onto the American midnight movie circuit, and later to home video.) The restored version got good reviews, and wider distribution, including a DVD release through Rhino Video.
The movie was digitally re-mastered and restored for its 30th anniversary. While the film footage was in reasonable shape, the optical soundtrack had degraded to the point where it was nearly unrecoverable. Director Joe Massot counted himself lucky they hadn't waited any longer than they had.
The painting on the professor's side of the "wonderwall" is a colorization of "The Passing of Arthur" black and white illustration by Florence Harrison from Alfred Lord Tennyson's "Guinevere and Other Poems". London: Blackie & Son, 1912. The original illustration has the caption "Morte d'Arthur"; it is not to be confused with the color illustration with the same title, done by the same artist for the same book.
The two poetic quotations that adorn the Professor's apartment are from two sources. The quotation above the "wonderwall" itself is from first two stanzas of the final section ("The Departure") of Alfred Lord Tennyson's "The Daydream", a retelling of the Sleeping Beauty Legend. The other is from near the beginning of "An End," by Christina Georgina Rossetti; this poem begins "Love, strong as death, is dead . . . "
Virtually all the soundtrack music was instrumental, with only occasional voices (and those slowed down, or in a foreign language). One lyrical song, "In The First Place", was recorded but not submitted; George Harrison didn't think it would suit Joe Massot. Harrison was mistaken, as it turned out; when the record turned up as the movie was being restored, Massot happily added it to the soundtrack, and a single was belatedly issued. Harrison was pleased to see the record come out, having learned that former Remo Four member Colin Manley was suffering from cancer, and the royalty payments would help with his bills. (Manley died in April 1999.)
When first approached to compose the movie's soundtrack, George Harrison replied "I don't know how to do music for films." When director Joe Massot promised to include whatever Harrison chose to write, Harrison accepted, composing songs as he was inspired by watching rushes of the unfinished movie, with the help of a stopwatch, to properly time the music to the scenes.