This is a constantly evolving list of digital-publishing links and resources we find useful and/or interesting.
The IDPF oversees the development of the specifications that make up epub. The actual specs are on their site. You will very rarely need these, but it’s good to know they’re there.
Epubcheck, the open-source tool for checking whether epubs are valid according to the relevant specs. If you run it yourself on your machine, you need to do so in a command line. Slightly technical, but really fast.
Liz Castro’s book focuses on creating epub from InDesign.
An example of how different CSS files applied to the same epub can radically change ebook design.
Free, good at batch conversions
Mike Shatzkin (business, strategy)
Michael Cairns (business, strategy)
Threepress Consulting (epub and web-based tech specialists)
Tools of Change (run by O’Reilly Media)
All those that Electric Book Works follows at http://twitter.com/electricbook are highly recommended.