Bummer, but it looks like "no" is the answer for now:
http://www.diesel-ebooks.com/support...kb&article=105
Sony has announced support for the Adobe Digital Editions, but it's not clear if that will be made available on the current Reader as an upgrade. If they do, it will open up other sources of books with Digital Rights Management (DRM) for the Reader other than the Sony Connect bookstore.
So, for the present you can read any pretty much any straight text, non-DRM'ed content on the Reader, but you may have to reformat it a bit (or a lot) and you can purchase and download DRM'ed content from Sony.
Highly formatted or graphics heavy documents (e.g. scientific papers, graphic novels) might not convert well, due to the fact that most are formatted for A4 or 8.5x11 inch pages which doesn't map very legibly to the much smaller Reader screen.
Note that non-DRM doesn't imply "public domain only". There are sources of current, copyrighted works on the web who sell their products in non-DRM formats that work fine on the Reader directly or with just a bit of re-formatting. My favorite is Baen Books; a list of others can be found in this thread:
https://www.mobileread.com/forums/showthread.php?t=11052
Sorry - no idea about the Eco question.
And welcome aboard!
Regards,
Bob