If you want to know everything.... - Tehanu @ 04:47 PST
Matt wrote in a while back with a link to Barnes and Noble's page on the "History of the Lord of the Rings" volume about to be published, and we did a blurb on it.
Matt wrote in again:
I'm not sure how much of the material therein is going to be new, seeing as it is a paperback, and much has already been written about the creation of LOTR by Christopher Tolkien.

However, I've found a link on Amazon UK to a soon-to-be-published 1,920 page hardcover title, "The Complete History of Middle-Earth: Part One", coming 2 October 2000. The book is going to cost 80 pounds UK!:

here it is

This looks to be the "big enchilada"....