Production Notes Section:
1. Chapter Titles.
The Chapter Titles, such as Doom in Chapter XXI., were not part of Twain's book. They remain from another version of this book. The chapter titles are used in PG's [Mark Twain index], so we have retained them.
2. The Author's Note.
The Author’s Note to Those Extraordinary Twins is actually the author's introduction to the novella, Those Extraordinary Twins. Twain originally produced this book with two parts: Pudd'nhead Wilson and Those Extraordinary Twins.
Project Gutenberg offers both stories, so we present the Author's Note as the Introduction to Those Extraordinary Twins, as Twain intended. If you want to read the Author's Note, please visit the Introduction of our production of the novella, [Those Extraordinary Twins].