Christopher Tolkien edited and published Unfinished Tales in 1980 as a collection of unfinished narratives by J.R.R. Tolkien.
The full title is Unfinished Tales of Númenor and Middle-earth. Christopher Tolkien selected and organized texts that expanded the histories and characters of Tolkien’s legendarium but had not been completed or finalized by their author.
The book includes material from the First, Second, and Third Ages. Its subjects include Númenor, the Istari, Galadriel and Celeborn, the Rohirrim, and the journey of the Black Riders. Some passages exist in multiple forms or contain editorial uncertainty.
That variation is why the book should not be read exactly like a finished novel. Christopher Tolkien often supplied explanatory notes and connecting material, while preserving contradictions where Tolkien’s manuscripts did not support a single definitive version. The work is separate from The History of Middle-earth, the later twelve-volume editorial series.