JRR Tolkien’s final posthumous book published

[Still Waters]

Though J.R.R. Tolkien passed away in 1973, he has never really stopped publishing. For decades his son and literary executor Christopher Tolkien has painstakingly catalogued and edited his father’s papers, creating new books out of unfinished and unpublished manuscripts. Most of those tales delve deep into the history of Middle-earth, the fantasy realm where Tolkien’s best known works, The Hobbit and The Lord of the Rings series take place. Now, it’s likely that work will come to an end with one last Tolkien book.

https://www.smithsonianmag.com/smart-news/jrr-tolkiens-final-posthumous-book-published-180970164/

[Orphalesion]

Just to clarify that a bit.
This isn't really a "book" like the Hobbit or the Lord of the Rings. It's a collection of material. Old and already published material. The various versions of the Fall of Gondolin, including the earliest one, which Tolkien wrote while on sick leave from WW I and which features Orcs riding in living steel tanks, have already been published, some for longer than 30 years. Pretty much the same with "Beren and Luthien", nothing of the JRR Tolkien-material in that "book" was new either, it had all been released previously in various forms.
These collections really just gather the material thematically and add some essays on the topic, penned by other authors. Nothing more.