Amazon has officially announced ?Kindle Unlimited?, a service offering unlimited reading and listening to Amazon?s ebook and audiobook library, for a subscription fee of $9.99 per month. The service includes access to over 600,000 ebooks and more than 2000 audiobooks from audible.com, and will be available to Kindles and kindle-enabled devices (such as smartphones running the Kindle app).

A new feature being introduced with Kindle Unlimited is WhisperSync for Voice. Whispersync allows you to seamlessly switch between reading an ebook and listening to an audiobook, without losing your place in the book.

With the announcement, Amazon is entering a field where they?ll compete with similar services like Scribd or Oyster. It?ll be interesting to see what impact a giant like Amazon has on this market.

Kindle Unlimited adds a new button to Amazon?s interface, labeled ?Read for Free with Amazon Unlimited?. It doesn?t seem as if there are any restrictions to how many books you can keep on your kindle, but the new service may cause some trouble among authors and publishers.

Over 600,000 books will be available on Amazon Unlimited(Hidden Content )

Over the past several years, Amazon has been in endless discussions with publishers over their prices, which the publishers believe are too low. With a service like Unlimited, which offers free reading, the subject of royalties may cause further complications with the publishers. Amazon is currently embroiled in a dispute with one publisher in particular, Hachette, and it is likely that this too, is in regards to digital book pricing.

The current library available for Amazon Unlimited includes The Hunger Games, Life of Pi, as well as the Harry Potter series and Lord of the Rings trilogy.