Pink Floyd were an English rock band who achieved worldwide success with their psychedelic and progressive rock music. Their work is marked by the use of philosophical lyrics, sonic experimentation, innovative album art, and elaborate live shows. Pink Floyd are one of the most critically acclaimed and commercially successful rock music groups of all time. It is estimated that they have sold over 200 million albums worldwide, including 74.5 million certified units in the United States.
The band originally consisted of university students Roger Waters, Nick Mason, Richard Wright and Syd Barrett. Founded in 1965, they first became popular playing in London's underground music scene in the late 1960s. Under Barrett's leadership they released two charting singles, "Arnold Layne" and "See Emily Play", and a successful début album, The Piper at the Gates of Dawn (1967). Guitarist and vocalist David Gilmour joined Pink Floyd several months prior to Barrett's departure from the group due to deteriorating mental health in 1968. Following the loss of their principal songwriter, Pink Floyd bassist and vocalist Roger Waters became the band's lyricist and conceptual leader, with Gilmour assuming lead guitar and sharing lead vocals. With this lineup Pink Floyd achieved worldwide critical and commercial success with The Dark Side of the Moon, Wish You Were Here, Animals and The Wall.
Wright left the group in 1979, and Waters in 1985, but Gilmour and Mason (joined by Wright) continued to record and tour. Waters resorted to legal means to try to keep them from performing as Pink Floyd, but the dispute was resolved with an out-of-court settlement which allowed Gilmour and Mason to continue, and which also released Waters from his contractual obligations to the band. Two further albums, A Momentary Lapse of Reason and The Division Bell followed. Following almost two decades of acrimony, the band reunited in 2005 for a single performance, at the charity concert Live 8.