What was J.R.R. Tolkien’s first published Middle-earth book after his death in 1973?

The Silmarillion was J.R.R. Tolkien’s first published Middle-earth book after his death in 1973.

The Silmarillion was edited by Tolkien’s son Christopher Tolkien and published in 1977. It presents the mythology and history behind The Hobbit and The Lord of the Rings, beginning with a creation account and continuing through the history of Arda and the First Age.

Its central section, the Quenta Silmarillion, concerns the Silmarils, three jewels made by the Elf Fëanor. Their theft by Morgoth leads to wars, oaths and tragedies that shape much of Tolkien’s earliest legendarium.

The book was not a finished novel prepared for publication exactly as Tolkien left it. Christopher assembled and edited material from different periods of his father’s life. Unfinished Tales followed in 1980, also edited by Christopher Tolkien.