The Silmarillion starts with the Ainulindalë, an account of the creation of the universe (there is a foreword and preface, but we'll skip that for simplicity's sake).
We start with Eru Ilúvatar. He is not some made up god, but rather a name in a made up language for the monotheistic God of Abrahamic religions. Tolkien was a rather devout Catholic, for those not in the know.
Anyway, the first thing Eru makes are the Ainur, a name meaning "holy ones." They are the offspring of His thought, meaning... who knows. Regardless, he starts teaching them music and they sing for him, alone or in small ensembles. Each individual Ainu only understands the part of Eru's mind they came from, but the more they sing and listen, the more they understand their siblings.
Then one day (if days exist in heaven), Eru says "Gather 'round, kids! I've got a new theme of music for ya, and once you learn it, y'all are gonna make a Great Music together. Feel free to embellish it if the mood strikes you. I'm just gonna listen to the beautiful music." Or something to that effect. Tolkien's prose is rather Biblical, after all.
And so, the Music starts. And it is glorious. And it stayed glorious until one Ainu, known as Melkor, decided "I hate classical. Let's get some death metal up in here." Melkor may have been the most powerful of the Ainu, but he had also become a rebel against Eru's wishes.
So he starts screeching his death metal, immediately causing discord and very unpleasant sounds to break out. Some start screeching right along with him. Eru smiled, probably used to Melkor's antics, and lifted up his left hand, beginning a new theme in the Music. This one was also lovely, but Melkor's death metal began overpowering many Ainu into silence. Eru broke out his serious business face, lifted his right hand, and a third theme began. This one started off quiet, but gained power and depth. Finally, it seemed that two different musics were playing at once: Melkor's screechy and repetitive, the other sorrowful and lovely and undaunted by Melkor's attempts at dominance.
Eru stood, and in one grand final chord, ended the Music.
Eru then speaks. "Melkor, you may think you've messed up my music, but trust me, you've only made it better." Melkor just sulks at this.
Eru goes over to a little patch of nothingness and says "Now, let's see what you've actually been doing." He then shows a simulation of a World. Yes, the Ainur literally sang the world's blueprint, though it has yet to actually come into existence.
Eru speaks many things to the Ainu, enough that they know much of what is and was and is yet to come, though not all. Only Eru knows it all. As the simulation runs, the Children of Ilúvatar, Elves and Men, are shown, which delight the Ainur to no end. Except Melkor, who saw only slaves to his whims. At this point, various Ainur take special interest in various natural phenomena. Ulmo for water and Manwë for air are given as examples.
But before the simulation reached it's end, it was shrouded with Darkness. Only then does Eru say "Let these things be!" And so, when some of the Ainur go into the world, they find it unshaped as of yet. Meaning that they didn't know they had been watching a simulation until that point. That's kind of funny.
It's also at this point that the Ainur in the world start taking physical form, often like unto the Children of Ilúvatar, though not always. Some are male and some are female, depending on... ummm... if they feel male or female, I guess.
Melkor comes into the world, too. He's all "I'm gonna prove Dad wrong and be the most awesome looking out of all of you and this world is gonna be mine, all mine, muahaha!"
So it's Melkor vs. the other Ainur as they try to make the world their own. Neither side ends up with what they originally intended, but eventually, the world starts to take shape in order to become habitable by the Children of Ilúvatar, Melkor's "nahnahnabooboo's" not withstanding.
Next time: role call!
