The Beatles were a British pop and rock group from Liverpool. They are widely regarded as the most successful group of the rock and roll era, having achieved broad popular success, critical acclaim and cultural influence. The group broke many sales records and charted more than 50 top 40 hit singles, including 20 #1's in USA alone. The band is estimated to have sold over a billion records worldwide (a figure, most likely, that in the forseeable future no other artist will ever come close to breaking).

Dubbed "The Fab Four" by some of their fans, the Beatles were John Lennon (1940–1980), Paul McCartney (born 1942), George Harrison (1943–2001), and Ringo Starr (born 1940). Lennon and McCartney were the principal songwriters, with Harrison making a significant contribution as the band matured. George Martin produced most of the Beatles' recordings.

The Beatles created a sensation in late 1963 in the UK (the phenomenon was dubbed "Beatlemania" by the British press), notable for the hordes of screaming and swooning young women the group inspired. Beatlemania came to North America in early 1964, and the band's popularity extended across much of the world. Within the space of five years, their music moved from the awakening of their early hits (such as "She Loves You" and "I Want to Hold Your Hand") to artistically ambitious suites of songs (such as the albums Sgt. Pepper's Lonely Hearts Club Band and Abbey Road). By writing their own songs, exploring the possibilities of the recording studio and working on unprecedented quality in every recording they released, the Beatles had far-reaching effects on popular music and made two feature films. They were subjected to unprecedented press scrutiny which included criticism of their later role as symbols of 1960s youth counterculture. The group disbanded in 1970.

John Lennon formed a skiffle group, The Quarry Men, in March 1957. On July 6 that year, he met Paul McCartney whilst playing at the Woolton Parish fete and the two were soon playing music together. In 1958 the young guitarist George Harrison joined the group, which played under a variety of names. In 1960 they travelled to Hamburg (particularly the infamous "Kaiserkeller" club) where they finally became the Beatles. Stuart Sutcliffe was part of the group in 1960-61 and influenced their appearance and sense of style. Allan Williams was their manager until 1962 when Brian Epstein took over the role.

In 1962, after having been rejected by every other record company in England, they joined EMI's Parlophone label. Their drummer for the past two years, Pete Best, was fired in favour of the more experienced Ringo Starr. The new line-up recorded their first broadcast interview on the hospital station Radio Clatterbridge. The Beatles' first sessions in September 1962 produced a minor UK hit, "Love Me Do", which likely charted partly because Epstein ordered a large quantity of the singles from EMI for his family's record stores. ("Love Me Do" subsequently reached the top of the US singles chart in May 1964.) This was quickly followed by the recording of their first album, Please Please Me, a mix of original songs by Lennon and McCartney along with some covers. The band's first televised performance was on a programme called People and Places broadcast live from Manchester by Granada Television on 17 October 1962.

Beatlemania began in Britain on 13 October 1963 with a televised appearance at the London Palladium. Although the band was experiencing great popularity in the record charts in England by early 1963, Parlophone's American counterpart, Capitol Records (which was owned by EMI), refused to issue the singles Love Me Do, Please Please Me and From Me To You in the United States, the reason being that no British act had ever made any impact on an American audience.

VeeJay Records, a small Chicago label, is said to have been pressured into issuing these singles as part of a deal for the rights to another performer's masters. Art Roberts, music director of Chicago powerhouse radio station WLS, placed "Please Please Me" into rotation in late February 1963, making it the first and last time a Beatles' record was heard on American radio until December 1963 (it lasted a few weeks at the bottom of the charts this first time around). Veejay issued a corresponding album that summer in America, which also went nowhere.

In August 1963 the Swan label (partly owned by Dick Clark) tried again with the Beatles' "She Loves You", which again failed to receive airplay. A testing of the song on his TV show American Bandstand resulted in laughter and scorn from American teenagers when they saw the group's unusual haircuts. Meanwhile, it is said that British airline stewardesses and others were bringing single copies of Beatles records into major US cities like New York, Chicago and Los Angeles to share with friends. In December 1963, during the weeks immediately following the Kennedy assassination, their music began slowly filling the American airwaves.

Beatlemania exploded in the United States with three national television appearances by the Beatles on The Ed Sullivan Show on 9 February, 16 February and 23 February 1964. The pop-music band became a worldwide phenomenon with worshipful fans and angry denunciations by cultural observers and established performers such as Frank Sinatra, sometimes on grounds of the music (which was thought crude and unmusical) or their appearance (their hair was considered 'scandalously long').

Some commentators have speculated that after the assassination of John F. Kennedy a depressed America was searching for a way out of gloom and despair. So in effect, the Beatles were in the right place at the right time (with a unique combination of talent and stage presence) to provide an enthusiastic jolt to a saddened nation.

During the week of April 4, 1964, they held the top five places on the Billboard Hot 100, a feat that has never been repeated.

In 1965 they were instated as Members of the Order of the British Empire. Lennon and Harrison began experimenting with LSD that year and McCartney would do likewise near the end of 1966.

In July 1966 Lennon caused a backlash against The Beatles when he claimed during an interview that Christianity was dying, quipping that the Beatles were "more popular than Jesus." Eventually he apologised at a Chicago press conference, acquiescing to objections by many religious groups including the Holy See as Beatles' records were banned or burned across the American South along with threats from groups such as the Ku Klux Klan.

The Beatles performed their last concert before paying fans in Candlestick Park in San Francisco on 29 August 1966. From this time until the group dissolved in early 1970, the Beatles concentrated on making some of the most remarkable recorded pop music of the 20th century. The group's compositions and musical experiments raised their artistic reputations while they retained their tremendous popularity. The Beatles' financial situation took a turn for the worse however, when their manager Brian Epstein died in 1967 and the band's affairs began to unravel. That same year, The Beatles became the first band ever globally broadcast on television but the members were drifting apart. Their final live performance was on the roof at the Apple studios in London in January 1969 during the difficult "Get Back" sessions (later used as a basis for the Let It Be album). Also in 1969, largely due to McCartney's efforts, they recorded their final album, Abbey Road. The band officially broke up in 1970 and a few months later Let It Be followed as their last commercial album release. Any hopes of a reunion were crushed when Lennon was assassinated in 1980.

However, a virtual reunion occurred in 1995 with the release of two original Lennon recordings which had the additional contributions of the remaining Beatles mixed in to create two hit singles: "Free as a Bird" and "Real Love". Three volumes (six CDs in total) of unreleased material and studio out-takes were also released, as well as a documentary and television miniseries, in a project known as The Beatles Anthology.