"Because" is a song written by John Lennon

John Lennon

John Winston Lennon, MBE was an English musician and singer-songwriter who rose to worldwide fame as one of the founding members of The Beatles, one of the most commercially successful and critically acclaimed acts in the history of popular music...

(credited to Lennon–McCartney) and recorded by The Beatles

The Beatles

The Beatles were an English rock band, active throughout the 1960s and one of the most commercially successful and critically acclaimed acts in the history of popular music. Formed in Liverpool, by 1962 the group consisted of John Lennon , Paul McCartney , George Harrison and Ringo Starr...

 in 1969. It features a prominent three-part vocal harmony by Lennon, McCartney and George Harrison

George Harrison

George Harrison, MBE was an English musician, guitarist, singer-songwriter, actor and film producer who achieved international fame as lead guitarist of The Beatles. Often referred to as "the quiet Beatle", Harrison became over time an admirer of Indian mysticism, and introduced it to the other...

, overdubbed three times to make nine voices in all. It first appeared on Abbey Road (1969), immediately preceding the extended medley

Medley (music)

In music, a medley is a piece composed from parts of existing pieces, usually three, played one after another, sometimes overlapping. They are common in popular music, and most medleys are songs rather than instrumental. A medley which is a remixed series is called a megamix, often done with tracks...

 on side two of the record.
The song begins with a distinctive electric harpsichord intro played by producer George Martin

George Martin

Sir George Henry Martin CBE is an English record producer, arranger, composer and musician. He is sometimes referred to as "the Fifth Beatle"— a title that he often describes as "nonsense," but the fact remains that he served as producer on all but one of The Beatles' original albums...

.