From Matthew White's website, the plot of the unwritten fourth book:
Discovered in Tolkein's papers long after his death were the notes for a new story. It was to be set in a new age of Middle Earth, long after the dwarves had been rounded up and herded into to bleak, rural reservations, long after the elves were no longer to be seen anywhere outside the Museum of Mythical Creatures. The new Middle Earth was a quiet, no-nonsense world of airports, malls and sitcoms, but then Bonnie Baggins found a ring of power in her grandmother's attic.
Discovered in Tolkein's papers long after his death were the notes for a new story. It was to be set in a new age of Middle Earth, long after the dwarves had been rounded up and herded into to bleak, rural reservations, long after the elves were no longer to be seen anywhere outside the Museum of Mythical Creatures. The new Middle Earth was a quiet, no-nonsense world of airports, malls and sitcoms, but then Bonnie Baggins found a ring of power in her grandmother's attic.