David Van Cortland Crosby (born August 14, 1941) is an American guitarist, singer, and songwriter. He is most well known for being a founding member of The Byrds, Crosby, Stills & Nash (CSN) and Crosby, Stills, Nash & Young (CSNY). Crosby is a member of the Rock and Roll Hall of Fame for his work in The Byrds and CSN.

Source: http://en.wikipedia.org/wiki/David_Crosby