What is an ePub File?
A file with the EPUB file extension is an Open Publication Structure eBook file.
The Open Publication Structure eBook format is a popular and freely available eBook standard so most EPUB files you find will probably be of this format.
How To Open an ePub File?
There is two way to open the file.
1. You can open this inside the Firefox using the EPUBReader, a free add-on that lets you read the contents of any ePub book.
2. You can download the software called FBReader and it is also free.
For first time right click on ePub file and select open with option there select the FBReader.