Unfinished Tales of Númenor and Middle-earth is a collection of both new stories and expansion of stories from The Silmarillion, The Lord of the Rings, and The Hobbit. That being said, it is absolutely necessary to read those books first prior to reading this one. Unfinished Tales of Númenor and Middle-earth is not a traditional novel, instead you should approach this book as a literary analysis by Christopher Tolkien on his father’s work and unpublished work. Given how incredibly complex The Silmarillion is, reading this book will make you comprehend it more (in my case love it even more). I know I found myself plenty of times being confused about certain characters, their relationships, and certainly their languages. In my opinion this book does a good job further explaining this. The writing style of this book is more like of The Hobbit and The Lord of the Rings. So unlike The Silmarillion, Unfinished Tales is a really easy and straight forward read.
This book consists of different stories. All of which at the end of each story Christopher Tolkien further explains something in particular about that story, including perhaps some inconsistencies or unfinished works regarding that story. In addition he also includes notes/comments made by his father regarding something about that particular story. Reading these portions of the book should make us really appreciate Christopher Tolkien’s work on editing his father’s unpublished work.
To say that Tolkien’s legendarium is complex, is an understatement. It’s absolutely amazing how much work J.R.R. Tolkien did in creating this amazing fantasy universe. Reading this book for example, gave me such appreciation to the different elven languages that he created. Everything from the different languages to the names of the characters, they all have a meaning that fits into the narrative of the story. And I think that is absolutely beautiful.