Which posthumous book by J.R.R. Tolkien was published in 1977 by his son Christopher?

The Silmarillion was published posthumously in 1977 by J.R.R. Tolkien’s son Christopher Tolkien. It presents a collection of myths, histories, and legends forming the foundation of Tolkien’s wider mythology.

Tolkien worked on versions of these stories for much of his life, but he never completed and arranged a final edition for publication. Christopher Tolkien edited material from many manuscripts and organized it into a coherent volume after his father’s death.

The book begins with a creation account and continues through the history of the world of Arda, including the First Age wars against Morgoth. It also contains the “Valaquenta,” “Quenta Silmarillion,” “Akallabêth,” and “Of the Rings of Power and the Third Age.”

Readers sometimes mistake The Silmarillion for a conventional sequel to The Lord of the Rings. It is instead a mythological history, with many narratives, genealogies, and changing textual traditions.