TOKYO - Your eyes probably hurt just thinking about it: Tens of thousands of Japanese cell-phone owners are poring over full-length novels on their tiny screens. Now, Japan's cell-phone users are turning pages. Several mobile Web sites offer hundreds of novels — classics, best sellers and some works written especially for the medium. It takes some getting used to. Only a few lines pop up at a time because the phone screen is about half the size of a business card. But improvements in the quality of liquid-crystal displays and features such as automatic page-flipping, or scrolling, make the endeavor far more enjoyable than you'd imagine. A library in one hand In the latest versions, cell-phone novels are downloaded in short installments and run on handsets as Java-based applications. You're free to browse as though you're in a bookstore, whether you're at home, in your office or on a commuter train. A whole library can be tucked away in your cell phone — a gadget you carry around anyway. "You can read whenever you have a spare moment, and you don't even need to use both hands," says Taro Matsumura, a 24-year-old graduate student who sometimes reads essays and serial novels on his phone. Such times could be just around the corner in the United States, where cell phones are become increasingly used for relaying data, including video, digital photos and music. U.S. publisher Random House recently bought a stake in VOCEL, a San Diego-based company that provides such mobile-phone products as Scholastic Aptitude Test preparation programs. Random House also said it reached licensing arrangements with VOCEL to provide cell-phone access to the publisher's Living Language foreign language study programs and Prima Games video game strategy guides. Cell-phone books are also gradually starting to get traction in China and South Korea. In Japan, though, some people are really getting hooked, finding the phone an intimate tool for reading. A recent marketing study by Bandai found that more than half the readers are female, and many are reading cell-phone books in their homes. Surprisingly, people are using cell-phone books to catch up on classics they never finished reading. And people are perusing sex manuals and other books they're too embarrassed to be caught reading or buying. More common is keeping an electronic dictionary in your phone in case a need arises.