We've published an initial, beta version of an ePub book for Nexus. To download it, go to the Nexus Book website, and click on the ePub download link. After filling out a simple registration form, you will receive an email pointing you to the download.
The current ePub file weighs in at 16 MB, and it contains all of the content from the online and PDF version of the book. eBook readers are a constantly moving target, from large format readers like the Kindle, Sony Reader, and iPad to smaller mobile platforms like Android and iPhone, and there is wide variation in how ePub readers interpret CSS and format text.
While we've done some basic initial testing to make sure that content is readable, there are still going to be some issues with code line width and figure sizes. We're looking for feedback on usability. If you download this epub, take some time to let us know at book@sonatype.com. Let us know: what device you were using, if you find code listings to be unusable due to width limitations, if you able to view all of the figures. We're especially interested in feedback from people viewing this content on an iPad.
Special thanks to Brian Jackson for taking the initiative to fork the Nexus Book git repository and add support for epub. In the process of adding this epub support, Brian also submitted some patches to the docbkx-maven-plugin.