The digital age has seen plenty of failed attempts at paperless book gizmos. But few have come from companies with as much stake in conventional books as Amazon, whose new Kindle adds to the e-book concept and is being introduced today (with great fanfare on their website). There are nearly 90,000 compatible book titles available for reading on the Kindle. The $399 device works without a computer, downloading books, newspapers, magazines, and selected blogs (why not the whole web?) directly via an EVDO wireless connection. No service plan is required; the cost of downloading is built into the price of individual titles (most New York Times bestsellers run $9.99). The high-res screen is black-and-white only, but the gadget weighs less than most paperbacks and can hold a couple hundred books at a time. Amazon CEO Jeff Bezos launched the Kindle today by calling the paper book “a 500-year-old technology” that is due for a makeover; skeptics will note that many 20-year-old $4 paperbacks are still running on their initial battery charge.