The Silmarillion, Tolkien's unfinished magnum opuswas compiled by his son, Christopher Tolkien, and published posthumously. Other posthumous works include The Children of Hurin, Unfinished Tales, The Histories of Middle-earth, and Roverandom.
The Children of Húrin was edited by Christopher Tolkien into final format and published in 2007.
The Silmarillian was edited and published by Tolkien's son, Christopher.
The Silmarillion. Tolkien began working on the story in 1917. It was the first book he ever wrote and the last one to be published. His son, Christopher Tolkien, edited his father's work and it was published in 1977, four years after his father's death.
Lord of the Rings was a series of three books.
Tolkien wrote it in the early 1930's. It was published in September 1937.It was published on September 21, 1937.
The Hobbit was the first book, but Tolkien published a number of others, including 'Mr. Bliss.'
"Hooray For Diffendoofer Day!", published in 1998, was written after Dr. Seuss's death, based on his sketches and notes. It was finished by Jack Prelutsky and illustrated by Lane Smith. Dr. Seuss (aka Theodor Seuss Geisel) passed away in 1991.
The book was written by H.R.F. Keating. The book is 189 pages in length and was published in the year 1976. It is written in English. It was published by the company called Warner Books.
I believe that would be The Sons of Hurin.
Posthumous Book- A book published after the authour's death.
The Lord of the Rings was basically written 1936 to 1949, and published 1954-1955. The content of Book V and VI was written sometime after 1944, and published in the LotR's third volume The Return of the King in October 1955.
He co-published with E. V. Gordon, a definitive edition of Sir Gawain and the Green Knight, in 1922.