Crosby, Stills, Nash and Young have posted a second song from the forthcoming 50th anniversary edition of their 1970 album, Déjà vu. “Ivory Tower” is a Stephen Stills song that didn't make it onto the album. He eventually included it on his 2013 compilation, Carry On. The 50th anniversary edition of Déjà vu will be released on May 14th.