edited by his son Christopher Tolkien will be published and released in 2021.

It will be titled "The Nature of Middle-earth'. All unpublished materials - written by his father - were sent to Carl F. Hostetter who heads the Elvish Linguistic Fellowship prior to Christopher
Tolkien's death.

Harper-Collins Publishers are releasing it in 2021.

I went crazy over J.J.Robbs latest releases... this will be added to my Tolkien collection in July 2021. LOLOL