Crosby, Stills & Nash (CSN) were an American-British-Canadian folk rock supergroup made up of David Crosby, Stephen Stills, and Graham Nash. They were known as Crosby, Stills, Nash & Young (CSNY) when joined by occasional fourth member Neil Young. They were noted for their intricate vocal harmonies, often tumultuous interpersonal relationships, political activism, and lasting influence on US music and culture. Crosby, Stills & Nash were inducted into the Rock and Roll Hall of Fame and all three members were also inducted for their work in other groups (Crosby for the Byrds, Stills for Buffalo Springfield and Nash for the Hollies). Neil Young has also been inducted, but as a solo artist and as a member of Buffalo Springfield, not for his work with the group.