Pink Floyd originally consisted of Syd Barrett (vocals, guitar), Richard Wright (keyboards, vocals), Roger Waters (bass, vocals) and Nick Mason[?] (drums) and named in tribute to two blues musicians, Pink Anderson[?] and Floyd Council[?]. Initially part of the underground rock scene, their material, mostly written by Barrett, was a mixture of US-influenced psychedelic rock and British whimsy and more than a touch of the blues, particularly in the guitar solos.
The sound was hardened somewhat in 1968 when guitarist David Gilmour joined the band. In 1969, Barrett suffered a mental breakdown, attributed to prolonged usage of psychedelic drugs (especially LSD). With Barrett's state becoming less and less predictable, the band's live shows became increasingly ramshackle until eventually the other band members simply stopped taking Syd to the concerts, with Waters and Gilmour taking his place as lead vocalists.
Whilst Barrett had written the bulk of the first record, Piper At The Gates Of Dawn (1967), he contributed little to the second A Saucerful Of Secrets (1968), forcing the band into a new direction. With the loss of their main songwriter the band seemed to lose direction: the next record, the double album Ummagumma (1969), was a mix of live recordings and unchecked studio experimentation by the band members. This continued on 1970's Atom Heart Mother, a UK number one now usually considered a dated psychedelic period piece and described by Gilmour as the sound of a band "blundering about in the dark."
The band's sound was considerably more focused on Meddle (1971), whose 23-minute song "Echoes" is often regarded as their first substantially successful lengthy piece of music, and which also included the atmospheric "One Of These Days" (now often regarded as a concert classic, with a distorted, disembodied one-line vocal) and the pop-jazz stylings of "St. Tropez".
Despite having never been a hit-single driven group, their massively successful 1973 album, Dark Side of the Moon featured a US number one track ("Money"), and more importantly remained in the top 100 for over a decade, breaking many records on the way, and making it one of the top selling albums of all time. Dark Side of the Moon itself was a concept album dealing with themes of (in?)sanity which, due to the use of Abbey Road studio's new 16-track recording equipment and the investment of an enormous amount of time by the group and engineer Glyn Johns, set new standards for sound fidelity. Dark Side of the Moon has also been the source of a persistent rumor that it was conceived as a kind of synchronized soundtrack for the film The Wizard of Oz.
Dark Side... and the three following albums (Wish You Were Here, Animals and The Wall) are often held up as the peak of Pink Floyd's career. The first of those, Wish You Were Here, released in 1975, is a tribute to Barrett in which the lyrics deal explicitly with the aftermath of his breakdown, including the lengthy and mainly instrumental "Shine On You Crazy Diamond" and the classic title track.
By 1977, and the release of Animals the band's music was starting to sound dated in the era of punk rock and they were often singled out (by The Sex Pistols' Johnny Rotten, amongst others) as symbolising how popular music had become flabby and pretentious, losing its way from the simplicity of early rock and roll. Animals contained more lengthy songs tied to a theme, taken in part from George Orwell's Animal Farm, which used pigs, dogs and sheep as metaphors for contemporary society.
The Wall gave Pink Floyd renewed critical acclaim and another hit single with the track "Another Brick in the Wall Part II," its catchphrase "We don't need no education, we don't need no thought control" catching the spirit of 1977 rather better than its predecessor. The Wall was written as a kind of rock opera concept film. The album itself was only pulled from what were considered the crucial and sellable songs from the soundtrack. It also became an incredibly expensive (and money losing) tour/stage-show. During this time, Roger Waters increased his artistic influence and leadership of the band, and Richard Wright was fired (though he performed on The Wall tour as a session musician).
The Wall remained on best-selling-album lists for 14 years.
After The Final Cut, bandmembers went their separate ways till 1987, when Gilmour attempted to revive the band with Nick Mason. A bitter legal dispute with Roger Waters ensued, but Gilmour and Mason achieved the legal right to release an album as Pink Floyd (Waters, however, gained the rights to some traditional Pink Floyd imagery, including almost all of The Wall). Richard Wright re-joined the duo near the end of the recording sessions of A Momentary Lapse of Reason as a session musician (though the newer remastered anniversary CD has revised this history and he is credited as a band member). By any account, Wright was a member of the band for the 1994 release of The Division Bell and its subsequent tour.
Pink Floyd are renowned for their lavish stage shows, combining over-the-top visual experiences with their music to create a show in which the artists themselves are almost secondary (and indeed, this was a major theme in the tour of The Wall, in which a band of session musicians played the first song, wearing rubber face masks - proving successfully that the band were not known for their individual personalities. Later in the show, a huge wall was built between the audience and the band. This show was notably performed by a number of guest bands assembled around Roger Waters in 1990 next to the Berlin Wall, before it was destroyed.
The lavish stage shows were also the basis for Douglas Adams' fictional rock group "Disaster Area" (creators of the loudest noise in the universe, and making use of solar-flares in their stage show!) in The Hitchhikers Guide to the Galaxy series. Douglas Adams was a personal friend of David Gilmour, and performed with Pink Floyd on the P.U.L.S.E tour.
Pink Floyd have not released any material since 1994's The Division Bell, and while they have not officially broken up, neither are there any rumours of any new album.