Because

AUTHORSHIP Lennon (1.00)
LENNON: "This is about me and Yoko in the early days. Yoko was playing some Beethoven chords and I said play them backwards. It's really Moonlight Sonata backwards." Beatles in Their Own Words

LENNON: "I was lying on the sofa in our house, listening to Yoko play Beethoven's 'Moonlight Sonata' on the piano. Suddenly, I said, 'Can you play those chords backward?' She did, and I wrote 'Because' around them. The song sounds like 'Moonlight Sonata,' too. The lyrics are clear, no bullshit, no imagery, no obscure references." September 1980, All We Are Saying: The Last Major Interview with John Lennon and Yoko Ono

McCARTNEY: "I wouldn't mind betting Yoko was in on the writing of that, it's rather her kind of writing: wind, sky and earth are recurring, it's straight out of Grapefruit and John was heavily influenced by her at the time." Paul McCartney: Many Years from Now

RECORDED
August 1, 1969, at Abbey Road, with overdubbing August 4 and 5

The intricate harmony singing was thoroughly rehearsed before recording began. The Long and Winding Road: An Intimate Guide to the Beatles

MARTIN: "Having done the backing track, John, Paul, and George sang the song in harmony. Then we overlaid it twice more, making nine-part harmony altogether, three voices recorded three times." The Complete BEATLES Recording Sessions; The Official Story of the Abbey Road Years 1962-1970

INSTRUMENTATION
McCARTNEY: bass, harmony lead vocal
LENNON: lead guitar, harpsichord, harmony lead vocal
HARRISON: Moog synthesizer, harmony lead vocal

MISCELLANEOUS
A piece of this music was first heard on John and Yoko's Wedding Album.

Later, when EMI were rationalising their instrument collection, Paul was able to buy the electric spinet which gives much of the characteristic sound to the track. He still has it in his recording studio along with many of the instruments used on Sgt. Pepper and Bill Black's stand-up double bass used on Elvis Presley's "Heartbreak Hotel," bought for him as a birthday present by Linda on a visit to Nashville.

COMMENTS BY BEATLES
LENNON: "This is a terrible arrangement, a bit like Beethoven's Fifth backwards." Hit Parader (April 1972)

McCartney and Harrison said this was their favourite song on the album. Beatles Forever

HARRISON: ". . . A bit like 'If I Needed Someone' - you know, the basic riff going through it is somewhat the same, but it's actually quite a simple tune. It's a three-part harmony thing which John, Paul, and myself all sing together. . . . I think this is possibly my favourite one on the album because it's so damn simple. The lyrics are uncomplicated, but the harmony was actually pretty difficult to sing. We had to really learn it, but I think it's one of the tunes that will definitely impress most people." Late 1969, The Beatles: A Celebration