Which Tolkien book did Christopher Tolkien publish in 1977?

Christopher Tolkien published The Silmarillion in 1977.

The Silmarillion appeared four years after J.R.R. Tolkien’s death, edited and arranged by his son Christopher Tolkien with assistance from the writer Guy Gavriel Kay. It presents a collection of myths and histories concerning the creation of the world, the divine Valar, the Elves, and the First Age of Middle-earth.

Unlike The Hobbit and The Lord of the Rings, The Silmarillion is not a single straightforward adventure novel. It contains several connected sections, including the creation account Ainulindalë, the account of the shaping of the world Valaquenta, and the long historical narrative Quenta Silmarillion.

Christopher worked from drafts that often existed in multiple versions and sometimes contradicted one another. The 1977 publication therefore reflects editorial decisions, while later volumes such as Unfinished Tales and The History of Middle-earth reveal more of Tolkien’s changing ideas.