A lot. The Middle-Earth saga alone spans five books and a few collections of short stories.
The Silmarillian was edited and published by Tolkien's son, Christopher.
The Children of Húrin was edited by Christopher Tolkien into final format and published in 2007.
J.R.R. Tolkien's novels, including "The Lord of the Rings" and "The Hobbit," were published by George Allen & Unwin.
I believe it was published in 1954.
"The Silmarillion" was written by J.R.R. Tolkien and published posthumously by his son, Christopher Tolkien, in 1977. It serves as a foundational work for the fictional universe of Middle-earth and delves into the mythology, history, and creation story of that world.
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.
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.
Tolkien left many sketches and drawings. He even doodled using colored pens during his train rides. The original hardcover versions of The Hobbit were published with his pictures and maps in them, and many of them have been used since then.There is a book, Pictures by JRR Tolkien that contain many of them.
Much of the base for the books comes from writing that became the Silmarilian, which Tolkien worked on for many years. He then wrote The Hobbit in the 1930's and the Lord of the Rings was done int eh 40's and 50's before publication. The Silmarillian was published after Tolkien's death by his son.
Tolkien intended for his books to be read and enjoyed by the world. The Silmarillion and some of his other works, however, where never completed or published.
I believe that would be The Sons of Hurin.
The Children of Húrin