If you are a lover of the printed word the graphic above may seem quite alarming: e-books were the number one format of books to be sold in the month of February 2011, surpassing adult hardcover and paperback sales. As Benedict Evans writes at paidContent, increases in e-book sales have coincided with the decline of paperback ones. While it's clear that e-books are gaining ground in the book market, the recent spike may not continue: according to the American Association of Publishers, the surge in February is largely a result of e-books being bought and loaded onto recently purchased e-readers from the holidays.