Unlike The Silmarillion, for which the narrative fragments were modified to connect into a consistent and coherent work, the Unfinished Tales are presented as J. R. R. left them, with little more than names changed (the author having had a confusing habit of trying out different names for a character while writing a draft). Thus some of these begin or end awkwardly, while others are simply collections of "factual" information about Middle-earth. Each tale is followed by a long series of notes explaining inconsistencies and obscure points.
Like The Silmarillion, it was edited and published before Christopher Tolkien embarked on a new study of his father's works, and as thus contains some factual errors because of over-editing or the use of source material which was superceded by later work, which at that time was not found yet. One particular example is the title of a part of the book, Narn i Hîn Húrin — in all original copies the title was Narn i Chîn Húrin, but this was changed for publication.
Unfinished Tales sold rather well, considering that it was a minimally-edited collection of posthumous works, and its success no doubt suggested embarking on the more ambitious work collectively titled The History of Middle-earth.
Though Unfinished Tales cannot be read as a book in its own right, any one who comes to it after reading The Lord of the Rings and The Silmarillion will indubitably find it interesting, as the book gives various nuggets of information about characters, events and places that are only hinted at in the other two books; e.g. the chapter on the Istari. 'Old' legends or myths of Middle-earth, like the actual story of Isildur's fall in the Gladden Fields, are given in their 'authoritative' versions. A number of other tales, like the history of Galadriel and Celeborn or the Black Riders' hunt for Frodo and the Ring, are told in different versions or from differing perspectives.
A particular gem is the story of Aldarion and Erendis, the only story of Numenor before its fall. A map of Numenor is also included in the book.
The First Age:
The First Age:Second Age: