What was the name of J.R.R. Tolkien's son who edited and published The Silmarillion?

Christopher Tolkien edited and published J.R.R. Tolkien's The Silmarillion.

J.R.R. Tolkien died in 1973 before completing a definitive publishable version of The Silmarillion. Christopher Tolkien worked through his father’s manuscripts, notes, drafts, and revisions to construct an edited edition. The book was published posthumously in 1977 by George Allen & Unwin.

The Silmarillion presents the mythic history of Tolkien’s invented world, beginning with creation and continuing through the First Age and later events. Unlike The Hobbit and The Lord of the Rings, it is not a single straightforward adventure novel. Its sections include the creation account, the history of the Silmarils, and material about Númenor and the Rings of Power.

Christopher’s role was editorial rather than that of a co-author who independently invented the whole published narrative. Because Tolkien left multiple versions of many stories, Christopher had to make careful choices about arrangement and wording. He later published extensive additional material in books such as Unfinished Tales and The History of Middle-earth.