book reader with the ability to wirelessly download books, injecting more competition in a small but fast-growing market by adopting a key feature of the rival Kindle from Amazon.com. Sony's $399 Reader Daily Edition will go on sale by December, Sony executives said Tuesday at an event at the New York Public Library. The device has a 7-inch (17.5-centimeter) touch screen and will be able to get books, daily newspapers and other reading material over cellular networks. Though Sony is following in Amazon's footsteps by adding wireless capability, its e-book strategy differs in crucial respects. Unlike Amazon, Sony has committed to an open e-book standard, meaning its readers can show copy-protected books from a variety of stores, and the books can be moved to and read on a variety of devices, including cell phones. Sony also announced Tuesday that the Readers will be able to load e-books “loaned” from local libraries. A library card will provide access to free books that expire after 21 days. The library connection “would seem to be something Amazon would never embrace, so that could be a key differentiator,” said Richard Doherty, director of research firm The Envisioneering Group.