It's a very thorough and hard read to follow examining how each country was formed, how arda itself was created and the how the Silmarils were taken.
It truelly is a great read, but it's no story, more like a documentation of Middle Earths historical timelines.
If you've read The Silmarillion, you should also read Unfinished Tales. It's an extension of The Silmarillion, and fills holes in certain histories missed by Christopher Tolkien.
Apart from "Leaf by Niggle," the Silmarillion is probably Tolkien's greatest work... from the heights of the creation, and the sheer poetry of the undying lands, to the depths of Middle earth and the bathos of the final passages, the Silmarillion encompasses everything that is great about mythology... written as a mythology for the English, to replace the bastardised remnants of their own, that had been butchered by the political needs of their French overlords, the Silmarillion magnificently fills the gap between prehistory and history... the fate of the children of Feanor is a tale worthy of this Island race, just as the Akallabeth is a fitting Atlantis for the descendants of Viking and Saxon....
It took me a long time to get through this book: in fact, I ended taking about a month break from it. 😄 It's quite a hefty book, almost reads like a textbook, really. But I stuck it out and I'm so glad I did! Its a wonderfully comprehensive work that ties in the books with the history of Middle Earth. Kudos To Tolkien, wherever you are 😎
Definitely a must-read for all Lord of the Rings fans. As said before, it describes the whole origin of that world and it's species and characters.
It does take a relentless reader to get trough the beginning, as Tolkien has created such a immense world with so much detail and needs to lay this out first to make the story and events understandable.
I read it after LOTR, and it gave me so much more insight in that story, wish I did it the other way around.