Amazon launches Kindle Books with Audio Companion to switch between reading and listening

Amazon has launched a neat new feature that allows users who buy certain books to switch between reading and audiobook listening. The database of titles is 45,000 strong and includes most new titles, thanks to Amazon’s recently purchase of Audible.

The feature is not free, but many titles cost only a few dollars to “upgrade” the Kindle version to one with an audio companion. Once upgraded, users can seamlessly switch between the two modes. Amazon has even created a tool that finds all upgradeable books from within one’s buying history.

The feature is available on all of Amazon’s apps, including iPhone, Android and Kindle tablets.