The Silmarillion was published posthumously in 1977 as a collection of myths about the creation and history of Arda.
The book opens with the Ainulindalë, a creation account involving Eru Ilúvatar and the Ainur, followed by the Valaquenta and the Quenta Silmarillion. These sections describe the shaping of the world, the rebellion of Melkor, and the wars surrounding the Silmarils.
Its narratives mainly concern the First Age, long before Bilbo’s adventure or the War of the Ring. Important figures include Fëanor, Beren and Lúthien, Túrin Turambar, and Eärendil.
Christopher Tolkien edited the posthumous volume from his father’s papers. It is best understood as a mythology and historical framework rather than a conventional novel, and its formal, archaic style differs sharply from The Hobbit.