Twain explains that the book must end here, for soon it will be the story of a man rather than a boy. If it were a book about adults, it would have to end with a marriage.
Twain's reluctance to continue the story to describe the boys' adult lives offers a bittersweet note. It is imperative for boys to grow up into men who comprehend their responsibilities in the world, but their lives will be less fun to describe.
Twain explains that his characters are still alive and doing well. He says that he won't reveal any more details about their lives at present, but he might want to write about them again some day.
Twain sets up the possibility of a sequel, Adventures of Huckleberry Finn.