Tales and legends chronicling the world's beginnings and the happenings of the First Age, focusing on the theft of the Simarils--the three jewels crafted by Fëanor--by Morgoth, first Dark Lord of Middle-earth.
The constant switching between fictional dialects made this very difficult to read.
I can't actually recall what happened in most of the book. Some of the characters seemed to go off in tangents that didn't impact the rest of the book.
The section on the Rings of Power and the third age was the best bit. It pretty much summarised the opening to the Fellowship of the Ring but then skipped everything up to Frodo throwing the ring into Mount Doom. It was also the only section where I could really work out what was happening.