The Silmarillion was published posthumously in 1977 as a collection of myths about Tolkien’s Elder Days.
The book was edited by Christopher Tolkien from manuscripts left by J.R.R. Tolkien, who died in 1973. It begins with creation and the Ainulindalë, continues through the Valaquenta, and then presents the major histories of the First Age. Its central conflicts include the creation of the Silmarils, the rebellion of Fëanor, and the wars against Morgoth.
The Silmarillion is often described as a mythology rather than a conventional novel because it combines narrative styles, summaries, annals, and legends. It is also distinct from The Book of Lost Tales, an earlier stage of Tolkien’s evolving mythology, and from Unfinished Tales, which was published later in 1980. The posthumous edition is therefore a carefully arranged presentation of Tolkien’s long-developed background materials.