The Silmarillion was published posthumously in 1977 and presents the mythology of Middle-earth. Tolkien’s son Christopher Tolkien edited the material for publication, with assistance from the fantasy writer Guy Gavriel Kay.
The book gathers stories from the creation of the world through the First Age, the history of the Silmarils, and later events involving Númenor and the Rings of Power. Its structure differs sharply from the narrative style of The Hobbit and The Lord of the Rings. It includes creation accounts, annals, legends, genealogies, and densely connected histories rather than one continuous adventure.
Tolkien worked on versions of these stories for decades, revising names, languages, and events repeatedly. Because he died before completing a definitive edition, the published book necessarily reflects editorial decisions. Unfinished Tales, published later in 1980, is a separate collection of narratives and background material rather than the title that introduced Tolkien’s main mythological synthesis.