Pink Floyd are an English rock band who initially earned recognition for their psychedelic or space rock music; and; as they evolved; for their progressive rock music. They are known for philosophical lyrics; sonic experimentation; innovative cover art; and elaborate live shows. One of rock musics most successful acts; the group have sold over 200 million albums worldwide including 74.5 million albums in the United States alone.Pink Floyd had moderate mainstream success and were one of the most popular bands in the London underground music scene in the late 1960s as a psychedelic band led by Syd Barrett; however; Barretts erratic behaviour eventually forced his colleagues to replace him with guitarist and singer David Gilmour. "Shine On You Crazy Diamond" is a nine-part Pink Floyd composition with lyrics written by Roger Waters in tribute to former band member Syd Barrett and music written by Waters, Richard Wright, and David Gilmour. It was first performed on their 1974 French tour. It was recorded for the 1975 concept album Wish You Were Here. The song was intended to be a side-long composition like "Atom Heart Mother" and "Echoes," but was.