Screenshot by Lance Whitney/CNET

Amazon has unveiled a new subscription service dubbed Kindle Unlimited that offers all-you-can-eat e-books and audiobooks for $9.99 per month.

Launched Friday, Kindle Unlimited lets you borrow as many books as you want at a single time from a collection of 600,000 Kindle titles and thousands of Audible audiobooks, with no due dates. Subscribers can find eligible titles by browsing the Kindle book store and looking for any book flashing the Kindle Unlimited logo. Simply click on the "Read for Free" link, and the book becomes available.

Subscribers will be able to listen to thousands of audiobooks from Amazon-owned Audible that are included with the Unlimited subscription. A complimentary three-month Audible membership expands the audiobook selection to more than 150,000 titles.

Unlimited subscribers can read or listen to their books on any Kindle device or any device with Amazon's Kindle app installed. That includes Kindle devices, iOS devices, Android devices, Windows Phone handsets, BlackBerry phones, PCs, and Macs.

Amazon's past e-book subscription efforts have been meager at best. Until now, the retailer offered a lending library with more than 500,000 e-book titles, but only for Prime subscribers and only one book per month. Kindle Unlimited puts Amazon in a better position to compete with other e-book subscription services, such as Oyster and Scribd. Oyster costs $9.95 a month, while Scribd charges $8.99 a month.

Amazon likely unveiled the new subscription service at this point to draw in buyers to its upcoming Fire smartphone. Launching July 25, the new phone will act as Amazon's portal to its online shopping and subscription services to try to turn Fire owners into dedicated customers.

So just what titles are available through Kindle Unlimited?

Among the 600,000 e-books are "The Lord of the Rings" trilogy, the "Harry Potter" series, the "Diary of a Wimpy Kid" books, "The 7 Habits of Highly Effective People," "The Princess Bride," and "Kitchen Confidential." Lovers of classic novels will find "Animal Farm," "2001: A Space Odyssey," "Cat's Cradle," and "The Good Earth." Amazon also offers popular reference series such as the "For Dummies" books and the "Lonely Planet" travel guides

More than 2,000 of the audiobooks will include the Whispersync for Voice feature so readers can switch between reading the book and listening to it. Some of the titles in this category include the "Hunger Games" trilogy, "Life of Pi," "The Handmaid's Tale," "The Man Who Mistook His Wife for a Hat," and "Boardwalk Empire."

Amazon promises Kindle exclusives with self-published e-books available only on the Kindle store, as well as printed books that have electronic versions available only through Kindle.

The company is offering a free 30-day trial for Kindle Unlimited.

"With Kindle Unlimited, you won't have to think twice before you try a new author or genre -- you can just start reading and listening," Russ Grandinetti, Kindle senior vice president, said in a statement. "In addition to offering over 600,000 eBooks, Kindle Unlimited is also by far the most cost-effective way to enjoy audiobooks and eBooks together. With thousands of Whispersync for Voice-enabled audiobooks to choose from, you can easily switch between reading and listening to a book, allowing the story to continue even when your eyes are busy."

The new subscription service is separate from Amazon's Prime membership service, which includes two-day shipping, streaming video, streaming music, and one-per-month e-book rentals.