Which Tolkien child became the principal editor of The Silmarillion after his father’s death?

Christopher Tolkien became the principal editor of The Silmarillion after his father’s death.

J.R.R. Tolkien died in 1973, leaving behind a large body of unfinished and revised material about the history of Middle-earth. Christopher, his third child, organized, edited, and sometimes selected among those drafts to create a publishable form of The Silmarillion, which appeared in 1977.

Christopher had extensive familiarity with the manuscripts and had worked closely with his father. He also drew maps and served as an important interpreter of Tolkien’s developing mythology. His editorial decisions shaped how many readers first encountered the First Age stories.

The Silmarillion was not a completed novel prepared for publication by J.R.R. Tolkien in the same way as The Hobbit. It was assembled posthumously from notes and versions spanning many decades. Christopher later published much more of that material in The History of Middle-earth, a twelve-volume series.