9The Silmarillion is Tolkien's first book and his last, the core of his imaginative work that underlies all his writings about Middle-Earth. Here are the legends of the Elder Days, the central stories that give meaning to the events of The Lord of the Rings and The Hobbit. The Silmarillion was begun in 1917, and Tolkien worked on it, changed it, and enlarged it throughout his life. Edited it by his son, Christopher Tolkien, the book finally appeared four years after the author's death.