J.R.R. Tolkien: History of Middle-Earth Part Four: The Shaping of Middle-earth edited by Christopher Tolkien

In The Shaping of Middle-earth the gradual transition from the "primitive" legendaria of The Book of Lost Tales to what would become The Silmarillion is described, and it contains a text which could be seen as the first "Silmarillion" - the "Sketch of the Mythology".

Three other parts are the Ambarkanta or "Shape of the World", a collection of maps and diagrams of the world described by Tolkien; and the Annals of Valinor and Beleriand, chronological works which started out as timelines but gradually turned into full narratives.