Amazon's Kindle hardware is already wildly successful, so it might seem counter-intuitive for the online megaretailer to offer Kindle apps for competitive devices like smartphones or tablets.
But Amazon knows that big profits won't come from selling one-off readers - but rather serving the insatiable demand for content to read on them. The more devices that are Kindle-compatible, the less need there is for rivals such as Apple iBooks and the forthcoming Google Bookstore.
The size of the Kindle library already blows away the competition - there are over half a million books available in electronic form to download direct to your phone or tablet including many best-sellers as well as 'proper' literature and thousands of free classics. There are even magazines and newspapers available for Kindle, although the high prices and less-than-interative experience of products such as The Times and The Economist make them a poor substitute for proper apps.
Refreshingly, you can share your Kindle books across devices - Android phones and tablets, Kindle readers, iPhones and iPads, even your desktop computer. And the WhisperSync software will even save your place so you can ditch the bookmarks.
Within the app it's simple enough to change font size and alter brightness or reverse the colours to relieve eyestrain. And being able to read wherever you want, without worrying about finding a reading light, is an unexpected joy.
It's a shame there's no built-in word definitions, but you can highlight words to search within the book or on Wikipedia or Dictionary.com - which means reading is a rewarding experience, even on a small screen. And with a host of Android-powered tablets waiting in the wings, it's hard to escape the possibility that the days of the paperback could be numbered.
Of course, many people love paper - and true bookworms may find that even the benefit of being able to carry your library around without breaking a sweat isn't enough to make up for the fact you can't fold down corners, scrawl notes in the margins, or pass on your favourite books on to your friends.
[Not a valid template]
The bottom line
Bookworms might balk at the prospect of reading on a smartphone, but paper's no match for Kindle's convenience - particularly when it comes to weighty reference books.