J.R.R. Tolkien’s unfinished mythological work published posthumously in 1977 was The Silmarillion.
The Silmarillion presents the creation of Tolkien’s world and the history of Arda, with particular attention to the First Age. It includes the Ainulindalë, the Valaquenta, the Quenta Silmarillion, the Akallabêth, and Of the Rings of Power and the Third Age. The central narratives include the making of the Silmarils and the wars against Morgoth.
Tolkien worked on related material throughout his life but did not complete a definitive final form. His son Christopher Tolkien edited and arranged the published volume after his father’s death. Unfinished Tales, The Book of Lost Tales, and The Children of Húrin are separate posthumous publications.