How to open ePub files
EPUB files can be opened in most e-book readers, including the B&N Nook, Kobo eReader, and Apple's Books app. EPUB files have to be converted before they're usable on the Amazon Kindle.
EPUB files can also be opened on a computer with several free programs
Calibre, Adobe Digital Editions
EPUB File Reader
Mac users can read EPUB files with Kitabu
Open in Browser
Windows 10 - Microsoft Edge browser — no additional software necessary.
Firefox Add-on (EPUBReader) and Chrome app (Simple EPUB Reader) that allow you to read EPUB files in the browser just like other documents.