Gaiman would have to come up with a different plot for a sequel to The Graveyard Book (though in The Jungle Books, Mowgli does come back to live in the jungle for a while, and then he and his friends get rather involved with the local human population briefly).
I'd like to read more about these characters too, but sometimes an idea is only big enough for one book. And Gaiman isn't especially well-known for sequels.
|