Amazon has launched another new incentive for Kindle owners that offers one of four editorially chosen eBooks a month for free to Prime subscribers. And even if you don't pay for a Prime subscription, you can still get one for 99p.

In addition, the books offered as part of the new Kindle First programme are available a month before their official release date.

Amazon Publishing editors chose four books that are eligible for Kindle First each month and list them on a dedicated part of the website. If you are logged in and a Prime member, you can choose one of them to download for free immediately. Unlike Kindle Lenders Library, also part of a Prime subscription, the eBook will be yours to keep.

The same is true for non-Prime subscribers, but instead of free, the books will be offered at a significant discount.

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All books acquired through Kindle First will also be available to read on all Kindle apps, no matter the device - another departure from content gleaned from the Kindle Lenders Library, which is only available on Kindle eBook readers.

The debut books are From the Cradle by Mark Edwards and Louise Voss, The Glassblower by Petra Durst-Benning, The Fallow Season of Hugo Hunter by Craig Lancaster, and mystery novel My Sisters' Grave by Robert Dugoni.

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Amazon also recently launched Kindle Unlimited in the UK, effectively its Spotify for books service that offers a large library of titles to be read at any time for a monthly subscription fee.