But what's taken a huge bite out of America's book budget is the rise of the trade paperback, those larger paperbacks of better quality that can now be found occupying prime real estate on tables at the front of bookstores. Since the 1980s, publishers have increasingly kept their backlist in trade paperback, and used this format to publish the paperback versions of books that don't have a mass-market appeal or million-copy sales potential, such as more-literary or specialized titles. Right now the price of most trade paperbacks hovers between $12 and $16, although nonfiction titles often cost more. (For example, this week's No. 1 New York Times bestseller, "John Adams," by David McCullough, costs $18.95, which makes you wonder how soon trade paperbacks will begin to regularly creep past the $20 barrier.)