- The Ainulindalë - the creation of Eä, Tolkien's universe.
- The Valaquenta - the Valar and Maiar, the deities and angels
- The Quenta Silmarillion - the history of the events before and during First Age
- The Akallabêth - the history of the Second Age
- Of the Rings of Power and the Third Age
The Silmarillion, together with other post-mortem collections of Tolkien's works, such as Unfinished Tales and The History of Middle-Earth, forms a narrative detailing the history of the universe where The Hobbit and The Lord of the Rings take place. Although reading the Silmarillion is not necessary to enjoy these books (it would probably spoil them), one can learn much more about Tolkien's world and its concepts by reading it.
The Silmarillion is a very complex work, employing an extremely wide array of themes, that originate in lore of countries all over Europe, but not adhering to any of them. Thus, the title of Eru Ilúvatar (One who is Father of All) is clearly a borrowed from the Norse mythology; the story of Túrin Turambar is very similar to a motive from Kalevala; and Nùmenor is obviously reminiscent of Atlantis (in fact, one of the names Tolkien gave that land was Atalantë).
Historically, the first drafts of the Silmarillion stories date back to as early as 1917, when Tolkien was hospitalized in a field hospital with trench fever. He tried to publish some the stories (in a very early version) some time in the 1920s; however most editors regarded them with suspicion (fairy tales for adults was not a popular concept then). He tried once more, having published the Hobbit in 1937; however that time too, the Silmarillion was found to be too complicated, and so Tolkien was asked to write a simple sequel instead (that sequel developed into the Lord of the Rings).
However Tolkien never abandoned these stories, probably seeing in them the genesis of Middle Earth as it is, the later events (The Hobbit and The Lord of the Rings) being only the aftershocks. The last drafts of Silmarillion stories were written just a short while before Tolkien's death in 1973. For several years, Christopher Tolkien worked on deciphering and connecting his father's drafts, which often were mere sketches. The final result, which was connected in a chronological sequence and made consistent, was published in 1977.
Currently, the Silmarillion is available in several prints, such as the 1990 version from Ballantine Books, ISBN 0-345-32581-8.