Houghton Mifflin Harcourt will publish The Fall of Gondolin by J.R.R. Tolkien, the second unpublished work by the late author of The Lord of the Rings. The title, set to be released in August, will be edited by Tolkien's son, Christopher Tolkien, with accompanying illustrations by Alan Lee.

The book, the publisher said, tells the story of "two of the greatest powers in the world," and their rival interests over the "marvelously hidden city" of Gondolin. At its center is Tuor, cousin of Túrin, chosen by the sea-god Ulmo to discover the great city before Middle-Earth's uttermost evil gets there first.

While living, Tolkien called the novel "the first real story of this imaginary world," in spite of it remaining unpublished. Together with Beren and Lúthien and The Children of Húrin, he regarded it as one of the three "Great Tales" of the "Elder Days" of Middle-Earth.

The Fall of Gondolin is the latest release in a series of fantasy works by Tolkien that were left unfinished, or revised and unpublished, and have subsequently been restored and edited for publication by his son. The first of these novels, The Children of Húrin, was released in 2007; it followed by the release of Beren and Lúthien in 2017. These two novels, along with The Fall of Gondolin, mark what HMH bills as a new "trilogy" of tales set in Tolkien's fantasy world of Middle-Earth.

The forthcoming volume will also include drawings and color plates by Lee, who also illustrated The Lord of the Rings and The Hobbit, and who also served as one of two lead concept artists for Peter Jackson's film adaptations of The Lord of the Rings, for which he won an Academy Award.