Originally Posted by Kretzer
One thing I would wish for in a future update is an option to make my own collections (or "folders" or "shelves" or whatever) in the library.
Kris confirmed this feature will definitely be available in a future Marvin version.
As to the read/unread feature, there's an easy fix for you... just ignore it.
I find it pretty useful to have a shelf of books I'm still about to read, as opposed to those I've already read. All of this will be moot, anyway, as soon as we get the option to create our own arbitrary book shelves.