“More mass-market paperbacks are still sold each day than any other type of book; last year consumers bought 535 million of them. But that number has steadily declined for a decade and is down 11 percent in the last five years, while the overall number of books sold has fallen just 7 percent.” Why the drop? “”We’ve been losing the foundation of our customer base because their eyesight is getting worse, and the books are getting harder and harder to read.” So major publishers are publishing big print editions.