What is a compilation album of previously unreleased songs and alternate takes recorded 1969–1980 by American singer-songwriter, who was one of the most popular acoustic artists of the decade and one of its best-selling artists?
Forever, John: Forever, John is a compilation album of previously unreleased songs and alternate takes recorded 1969–1980 by American singer-songwriter John Denver. John Denver:  Starting in the 1970s, he was one of the most popular acoustic artists of the decade and one of its best-selling artists.
Forever, John