Found this at this source:
https://lrmonline.com/news/what-material-does-amaz...One burning question fans have had is what material does Amazon have the rights to for The Rings of Power show? Well we know have an answer courtesy of the showrunners J.D. Payne and Patrick McKay in a recent interview with Vanity Fair. The trade was asking questions fans wanted to know the answers to and this was definitely one of the questions that was endlessly debating among the Tolkien fan base.
So what did Amazon buy? “We have the rights solely to The Fellowship of the Ring, The Two Towers, The Return of the King, the appendices, and The Hobbit,” Payne says. “And that is it. We do not have the rights to The Silmarillion, Unfinished Tales, The History of Middle-earth, or any of those other books.”