The Silmarillian was edited and published by Tolkien's son, Christopher.
Mabel Tolkien died in 1904 of acute Diabetes.
Agatha Christie was working on her autobiography at the time of her death in 1976. The book was titled "An Autobiography" and was published posthumously in 1977.
A posthumous book is one published after the author has died.
JRR Tolkien ( John Ronald Reuel Tolkien) died on September the 2nd, 1973, at age 81.
As a matter of fact, he had three sons. These were John Tolkien, Michael Tolkien, and Christopher Tolkien. His third son, Christopher, is the most famous, because he compiled and published several works that J.R.R. Tolkien had died without releasing. Much of what we know about the early history of Middle-earth we owe to him.
"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.
J.R.R. Tolkien was in his early 30s when he began writing "The Hobbit," which was published when he was 45 years old. He was in his early 60s when "The Lord of the Rings" was published.
Mabel Tolkien, the mother of J.R.R. Tolkien, died on November 14, 1904.
Tolkien died on 2 September 1973. He was buried next to his wife Edith.
Michael Tolkien died in 1984, in England, UK.
Tolkien was 12 years old when his mother died. His guardian was a Catholic Priest.
J.R.R. Tolkien died September 2, 1973 of natural causes at age 81.