Mickey Hart is a drummer, an ethnomusicologist, and an author. He joined the Grateful Dead as its second percussionist in 1967. In 1970, Hart left the Dead and cut the solo album Rolling Thunder in 1972, featuring various members of the Dead. Hart returned to the band in 1974. Hart's musical activities outside the Dead have been extensive. In 1976, the Dead's Round Records label released Diga by the Diga Rhythm Band, an early experiment in worldbeat fusion put together by Hart.