WOW, Thank you everyone! I feel overwhelmed!
I have a lot to look into and consider it seems.
The Opus supports
Adobe® ePUB/PDF Reader
Multi-format readerHTML, TXT, JPG, GIF, PNG
According to my research, any books bought or loaned in Denmark, through Danish sites and the library, would require something that can read Adobe digital editions format and EPub. I assume this is the same thing that the Opus can do?
Another question...If I bought an Opus, could it also work with books bought at sites like Amazon?
And...(oh, the questions keep coming!) is an E-Ink screen the same as the liquid paper function on other ebook readers?