Originally the story was called "Those Extraordinary Twins." I meant to make it very short. I had seen a picture of a youthful Italian "freak" -- or "freaks" -- which was -- or which were -- on exhibition in our cities -- a combination consisting of two heads and four arms joined to a single body and a single pair of legs -- and I thought I would write an extravagantly fantastic little story with this freak of nature for hero -- or heroes -- a silly young Miss for heroine, and two old ladies and two boys for the minor parts. I lavishly elaborated these people and their doings, of course. But the tale kept spreading along and spreading along, and other people got to intruding themselves and taking up more and more room with their talk and their affairs. Among them came a stranger named Pudd'nhead Wilson, and a woman named Roxana; and presently the doings of these two pushed up into prominence a young fellow named Tom Driscoll, whose proper place was away in the obscure background. Before the book was half finished those three were taking things almost entirely into their own hands and working the whole tale as a private venture of their own -- a tale which they had nothing at all to do with, by rights.
-- Mark Twain