Is this the oldest bestseller ever? Publishers routinely set release dates far in advance, and keep a book's secrets under wrap to build anticipation, but Mark Twain's demand that his memoir be published a century after his death surely must set some kind of record. Hugely underestimating its audience, the University of California Press planned a first print run of 7,500 copies—but they've already printed 275,000 so far. The publisher cannot print copies fast enough, as bookstores across the country demand more copies of the 500,000-word tome in advance of the holiday season. “It’s totally the Dad book of the year,” said one bookseller. The Michigan printer producing the books is working overtime, churning out 30,000 copies a week.