I have read The Hobbit, The Lord of the Rings and The Silmarillion, I am currently reading Unfinished Tales and I plan to read the three Great Tales books. I also plan to read some selected parts of The History of Middle-earth. I'm not that interested in earlier versions of stories published elsewhere, or collections of information that mainly summarise information from other books. What I'm looking for is the most final versions of stories and collections of information that aren't included in other works or greatly expand upon what is included in other works (similar to the content of Unfinished Tales). In any case, I will borrow the books from a library so I will not buy any of them.