From Publishers Marketplace :
In the good news, Hachette is essentially printing money with the Twilight series. I can't find the article right now (I think it was in PW) but it said that Hachette can't fill the orders for Twilight fast enough. They are printing 7.5 million more copies and that they sometimes have 8 printing presses going at the same time. To date, the series has sold 25 million copies. It's fairly amazing to me how one book can really carry a whole publishing house. For Scholastic, it was the Harry Potter series. For Simon & Schuster, it was The Secret. But these books seem to be an anomaly. Is it really wise to place so much of the economic success of a business on one product?