“We have the rights solely to The Fellowship of the Ring, The Two Towers, The Return of the King, the appendices, and The Hobbit,” He said. “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.”
“There’s a version of everything we need for the Second Age in the books we have the rights to,” McKay noted. “As long as we’re painting within those lines and not egregiously contradicting something we don’t have the rights to, there’s a lot of leeway and room to dramatize and tell some of the best stories that [Tolkien] ever came up with.”