Just as music lovers enjoy large collections of songs without owning CDs, tapes or vinyl records, readers increasingly pull current best-sellers and classic literature from electronic menus rather than bookshelves. The Association of American Publishers reports that e-book sales jumped 207 percent in the first five months of this year, and Amazon now sells more digital books than hardbacks -- a tipping point reached last spring. During July, customers of the web retailer bought 180 e-books for every 100 hard-cover copies sold. The company, which just introduced its third-generation Kindle reader, expects to move more e-books than paperbacks by the end of 2011.
Other popular devices include the Sony Reader, the Nook from Barnes & Noble and Apple's iPad. Google also plans to enter the market.

Consumers benefit from a price war among e-reader brands (see video below) and from technology innovations, such as Sony touch screen features and multimedia books from three publishers that integrate photos and videos to supplement the text -- particularly for the iPad with a large, color screen. "It's a wide-open world," explains Molly Barton of Penguin Group, a major publisher. "You can show readers the world around the books that they're reading."
In addition to convenient access, storage and lightweight portability, e-books have "green" advantages by eliminating paper and not requiring fuel for printing and delivery. Plus, they won't wind up in landfills. On the flip side, there's no universal format that lets e-books be viewed on any brand of reader. Amazon doesn't support an "e-pub" standard used by some competitors and many libraries.

The fast-paced growth forces a fresh look at best-seller lists. Though downloads account for more than 8 percent of consumer book purchases, USA Today is the only national publication tracking e-books and including them in overall popularity rankings. There's pressure to close that digital divide, including from authors. Stephenie Meyer (Twilight series) and Stieg Larsson (The Girl With the Dragon Tattoo) are among writers who've sold at least 500,000 books for the Kindle.

Amazon founder says: "If it's a book about music history, having music people can play at certain points in the book can be useful. Maybe biology textbooks can benefit from certain animations." -- Jeff Bezos, CEO

Blogger says: "A shiny new Kindle or iPad or Kobo or Nook won't convert a non-book buyer into a rabid book buyer. It might give us some incremental growth. But not revolutionary growth. The market isn't bigger than we thought. It's exactly the size we were afraid it might be." -- John Mesjak, publishers' sales representative blogging at my3books.com

Columnist says: "That the success of the Kindle is good news for Amazon should go without saying. But it represents a remarkable environmental advance as well." -- Reihan Salam, Forbes magazine