J.R.R. Tolkien’s first published posthumous Middle-earth collection edited by Christopher Tolkien was The Silmarillion.
The Silmarillion was published in 1977, four years after Tolkien’s death, with Christopher Tolkien editing and arranging material from his father’s extensive writings. It presents the mythology and history of Tolkien’s world from its creation through the First Age and beyond.
The book includes the Ainulindalë, the Valaquenta, the Quenta Silmarillion, the Akallabêth, and the concluding section about the Rings of Power. Its central First Age stories include the wars over the Silmarils and the histories of figures such as Fëanor, Beren, Lúthien, Túrin, and Eärendil.
The Silmarillion was not a finished novel in the same sense as The Hobbit or The Lord of the Rings. Christopher Tolkien shaped diverse versions into a publishable volume, which is why later editorial works explore some of the same stories in greater detail.