some things I learned from reading The Nature of Middle-earth

Read them here.

It's all about NoME (a great abbreviation, as the book is gnomic in more than one sense).

You should also read Jeff LaSala's thoughtful piece on the subject.

I have one quibble with Jeff. He calls NoME "kind of an unofficial thirteenth installment" for the 12-volume History of Middle-earth, but the 13th volume of HoME already existed before the series was published. It's Unfinished Tales, most of which would have fit very nicely in parts 2-4 of The Peoples of Middle-earth, v. 12 of HoME, if it hadn't already appeared.

But then what about John D. Rateliff's 2-volume The History of The Hobbit? That too surely qualifies. So that makes NoME at least v. 16.