Which author completed and edited J.R.R. Tolkien's The Silmarillion for publication?

Christopher Tolkien completed and edited J.R.R. Tolkien’s The Silmarillion for publication.

J.R.R. Tolkien worked on the mythology behind The Silmarillion for much of his life, but he did not finish a definitive publishable version before his death in 1973. His son Christopher organized material from drafts, notes, and variant texts, then prepared the posthumous book for publication.

The Silmarillion appeared in 1977, with assistance from the fantasy author Guy Gavriel Kay. It presents the creation of Eä, the history of the Elves, the wars against Morgoth, and later events leading toward the world of The Lord of the Rings.

Because Christopher edited multiple versions, the book is not simply a manuscript Tolkien had left in final form. It is a carefully assembled editorial work based on his father’s writings. Christopher later published extensive collections of Tolkien’s drafts and notes in The History of Middle-earth.