The Lost Road and Other Writings

An unfinished time-travel novel Tolkien began in the late 1930s, after a challenge from C.S. Lewis for each of them to write a story. Lewis tackled space travel (Out of the Silent Planet), Tolkien tackled time travel. Tolkien abandoned it after a few chapters.

Volume Five of twelve. It bridges the early mythological volumes and the later volumes that trace the writing of The Lord of the Rings.

Yes -- the time-travel sequence was intended to culminate in the fall of Numenor, making the novel a bridge between the Silmarillion mythology and the modern world. The concept of Numenor as a memory of Atlantis originates in this abandoned project.

An essay by Tolkien on the families and history of the languages of Middle-earth -- a linguistic genealogy tracing how Elvish and other tongues developed and diverged.