ePub Reader is a simple and powerful extension that can open any document with a ".epub" file extension. ePub is a new e-book file format for viewing online or offline documents. Please read this (https://en.wikipedia.org/wiki/EPUB) Wikipedia page to get more info about the ePub file format. To work with this add-on, please right-click on any ePub link and then click on the - View ePub - item from the context menu. Alternatively, you can open the popup window and then add the epub link in the UI (top section) to view the document. For offline files, simply drag & drop the file to the designated area in the popup in order to load the ePub document. There are several views to render the document, please select them from the top toolbar within the UI. Moreover, you can resize the window to your desired size and the document will adapt itself to the new size. Note: this add-on uses an open-source JavaScript library called "epub.js" in order to render the ".epub" file format. Please visit this (https://github.com/futurepress/epub.js/) GitHub page to get more info about this library. If you have a feature request or found a bug to report, please fill the bug report form on the addon's homepage (https://mybrowseraddon.com/epub-reader.html).