Create a New Open Textbook
If you use Google docs as a means of creating information, you’ll be happy to note that you now have the ability to create an ePub file from this system. This is what Google has to say about this:
EPUB is the most widely supported file format for publishing accessible documents and digital books, allowing people to consume long-form content in their preferred apps on a diverse range of screen sizes and devices, including smartphones, tablets, and eReaders. To make it easier for authors, publishers, and academic institutions to create works that can be consumed digitally, Google has launched the ability to export Google Docs files as EPUB publications. Simply go to the File menu > Download as > EPUB Publication (.epub).
For more information, see instructions on the Google website.