J. R. R. Tolkien
The request for a sequel prompted Tolkien to begin what would become his most famous work: the epic novel "The Lord of the Rings" (originally published in three volumes 1954–1955). Tolkien spent more than ten years writing the primary narrative and appendices for "The Lord of the Rings", during which time he received the constant support of the Inklings, in particular his closest friend C. S. Lewis, the author of "The Chronicles of Narnia". Both "The Hobbit" and "The Lord of the Rings" are set against the background of "The Silmarillion", but in a time long after it.
Christopher Tolkien
Tolkien had long been part of the critical audience for his father's fiction, first as a child listening to tales of Bilbo Baggins (which were published as "The Hobbit"), and then as a teenager and young adult offering much feedback on "The Lord of the Rings" during its 15-year gestation. He had the task of interpreting his father's sometimes self-contradictory maps of Middle-earth in order to produce the versions used in the books, and he re-drew the main map in the late 1970s to clarify the lettering and correct some errors and omissions. J. R. R. Tolkien invited Christopher to join the Inklings when he was twenty-one years old, making him the youngest member of the informal literary discussion society that included C. S. Lewis, Owen Barfield, Charles Williams, Warren Lewis, Lord David Cecil, and Nevill Coghill.