It's really impossible to rate this book. If you are a hardcore Tolkien fan, I think you'll love it. If you thought The Silmarillion was a difficult read, you'll probably want to skip this one.

Basically, this book is a printing of Tolkein's early drafts of tales that eventually came to comprise the Silmarillion, along with his son Christopher's commentary. Much of this material was ultimately rejected in the final versions, and there were some major changes to much of the material.

So, if you are interested in seeing Tolkien's thought process in creating and developing Middle Earth, and are willing to put in the effort required to keep up with all the changes, this book is for you. If you are looking for a fantasy story in which you can lose yourself in the prose, you might want to give this one a miss.