Before The Silmarillion, The Hobbit and The Lord of the Rings, the earliest myths and legends of Middle-earth and Valinor were laid down in The Book of Lost Tales, written by J.R.R. Tolkien between 1916 and 1920, and compiled by Christopher Tolkien for publication in 1983.

The Book of Lost Tales stands at the beginning of the entire conception of Middle-earth and Valinor, for the Tales were the first form of the myths and legends that came to be called ...