E-book sales have better than doubled year-to-year, the Association of American Publishers said. A new study put out on Thursday saw e-book sales surge 115 percent in January to produce $69.9 million in revenue versus just a year ago. The rush came as regular hardcover books lost 11.3 percent of their revenue to hit $49.1 million, paperbacks fell 19.7 percent to $83.6 million, and "mass market" books plunged 30.9 percent to $39 million.
