Which 1977 book did Christopher Tolkien edit and publish from J.R.R. Tolkien’s writings?

The Silmarillion was edited and published by Christopher Tolkien in 1977 from J.R.R. Tolkien’s writings.

J.R.R. Tolkien died in 1973, leaving a large and complex body of mythology in different drafts and versions. Christopher Tolkien organized, selected, and edited this material into a publishable volume, working with the fantasy writer Guy Gavriel Kay during part of the process.

The book presents the creation of the world, the divine Valar, the Elves, and major First Age stories such as the wars against Morgoth. It is not a straightforward novel in the style of The Hobbit. Its forms include mythology, annals, narrative, and genealogical material, reflecting the unfinished state of Tolkien’s larger legendarium.