The Silmarillion recap

The Silmarillion recounts the mythic history of the world from its making to the end of its First Age. After the world is shaped by the music of the angelic Ainur, the rebellious power Morgoth corrupts and darkens it. The Elf Feanor crafts the Silmarils, three jewels holding a holy light; when Morgoth steals them and destroys the light of the world, Feanor and his people swear a terrible oath to reclaim them and pursue Morgoth back to Middle-earth, an act stained by kin-slaying and doom. Across long wars the Elves and their mortal allies fight Morgoth and are gradually broken. Amid the ruin come the great legends: Beren and Luthien, who together wrest a Silmaril from Morgoth's crown, and the tragic Turin, undone by a curse. At last the mariner Earendil sails to plead with the powers of the West, who come in force, cast Morgoth down, and end the First Age, though the world is forever changed and diminished.

This work is a mythological history of the world's creation and its early ages, told in the high style of legend. It begins with the One, Iluvatar, and the angelic spirits called the Ainur, whose great music shapes the design of the world. Some of these powers descend into the world to order and tend it, while the mightiest among them falls into pride and rebellion, sowing the first discord. Against this vast background the histories of the Elves and of Men unfold.

The First Age ends with the War of Wrath, in which the powers of the West overthrow Morgoth, break his strongholds, and cast him out of the world into the void. Of the three Silmarils, one is lost into the sea, one into the depths of the earth, and one kept aloft in the sky with the mariner Earendil, becoming a bright star of hope. The oath sworn over the jewels destroys nearly all who bound themselves to it. The surviving Elves diminish and many depart over the sea, while the age of Men begins. The book then carries the history further, telling of the rise and drowning of the island kingdom of Numenor and, in its final part, of the forging of the Rings of Power and the long shadow of Morgoth's servant Sauron, linking these ancient legends to the later age of The Lord of the Rings.