Born and raised in Liverpool, Lennon became involved in the skiffle craze as a teenager; his first band, the Quarrymen, was named the Silver Beatles, and finally evolved into the Beatles in 1960. When the group disbanded in 1970, Lennon embarked on a sporadic solo career that produced albums including John Lennon/Plastic Ono Band and Imagine, and songs such as "Give Peace a Chance", "Working Class Hero", and "Imagine". After he married Yoko Ono in 1969, he added "Ono" as one of his middle names. Lennon disengaged himself from the music business in 1975 to raise his infant son Sean, but re-emerged with Ono in 1980 with the new album Double Fantasy. He was shot and killed in front of his Manhattan apartment three weeks after its release.

Lennon revealed a rebellious nature and acerbic wit in his music, writing, drawings, on film and in interviews. Controversial through his political and peace activism, he moved from London to Manhattan in 1971, where his criticism of the Vietnam War resulted in a lengthy attempt by the Nixon administration to deport him. Some of his songs were adopted as anthems by the anti-war movement and the larger counterculture.

McCartney has been recognised as one of the most successful composers and performers of all time More than 2,200 artists have covered his Beatles song "Yesterday", making it one of the most covered songs in popular music history. Wings' 1977 release "Mull of Kintyre" is one of the all-time best-selling singles in the UK. A two-time inductee into the Rock and Roll Hall of Fame (as a member of the Beatles in 1988, and as a solo artist in 1999), and a 21-time Grammy Award winner, McCartney has written, or co-written, 32 songs that have reached number one on the Billboard Hot 100, and as of 2009 he has 25.5 million RIAA-certified units in the United States. McCartney, Lennon, Harrison and Starr all received appointment as Members of the Order of the British Empire in 1965 and, in 1997, McCartney was knighted for services to music. McCartney is also one of the wealthiest musicians in the world, with an estimated net worth of US$1.2 billion.

McCartney has released an extensive catalogue of songs as a solo artist and has composed classical and electronic music. He has taken part in projects to promote international charities related to such subjects as animal rights, seal hunting, land mines, vegetarianism, poverty, and music education. He has married three times and is the father of five children.

Harrison's earliest musical influences included George Formby and Django Reinhardt; Carl Perkins, Chet Atkins and Chuck Berry were subsequent influences. By 1965, he had begun to lead the Beatles into folk rock through his interest in the Byrds and Bob Dylan, and towards Indian classical music through his use of the sitar on "Norwegian Wood (This Bird Has Flown)". Having initiated the band's embracing of transcendental meditation in 1967, he subsequently developed an association with the Hare Krishna movement. After the band's break-up in 1970, Harrison released the triple album All Things Must Pass, a critically acclaimed work that produced his most successful hit single, "My Sweet Lord", and introduced his signature sound as a solo artist, the slide guitar. He also organized the 1971 Concert for Bangladesh with Indian musician Ravi Shankar, a precursor for later benefit concerts such as Live Aid. In his role as a music and film producer, Harrison produced acts signed to the Beatles' Applerecord label before founding Dark Horse Records in 1974 and co-founding HandMade Films in 1978.

Harrison released several best-selling singles and albums as a solo performer, and in 1988 co-founded the platinum-selling supergroup the Traveling Wilburys. A prolific recording artist, he was featured as a guest guitarist on tracks by Badfinger, Ronnie Wood, and Billy Preston, and collaborated on songs and music with Dylan, Eric Clapton, Ringo Starr and Tom Petty, among others. Rolling Stone magazine ranked him number 11 in their list of the "100 Greatest Guitarists of All Time". He is a two-time Rock and Roll Hall of Fame inductee – as a member of the Beatles in 1988, and posthumously for his solo career in 2004

Harrison's first marriage, to model Pattie Boyd in 1966, ended in divorce in 1977. The following year he married Olivia Harrison (née Arias), with whom he had one son, Dhani. Harrison died in 2001, aged 58, from lung cancer attributed to years of cigarette smoking. His body was cremated and his ashes were scattered in the Ganges and Yamuna rivers in India, in a private ceremony according to Hindu tradition. He left an estate of almost £100 million.