The History of Middle-earth

The History of Middle-earth is a 12-volume series of books that collect and analyze material relating to the fiction of J. R. R. Tolkien, produced by his son Christopher Tolkien. They are extremely detailed, to the point of documenting scraps of paper that have been erased multiple times with hundreds of footnotes.

1. The Book of Lost Tales 1 (1983)
2. The Book of Lost Tales 2 (1984)
3. The Lays of Beleriand (1985)
4. The Shaping of Middle-Earth (1986)
5. The Lost Road and Other Writings (1987)
6. The Return of the Shadow (The History of The Lord of the Rings v.1) (1988)
7. The Treason of Isengard (The History of The Lord of the Rings v.2) (1989)
8. The War of the Ring (The History of The Lord of the Rings v.3) (1990)
9. Sauron Defeated (The History of The Lord of the Rings v.4) (1992)
10. Morgoth's Ring (The Later Silmarillion v.1) (1993)
11. The War of the Jewels (The Later Silmarillion v.2) (1994)
12. The Peoples of Middle-earth (1996)