How do you "HIDE" books in your bookshelf on the reader tho?
As far as I can see, you can only hide works on the online bookshelf, but it's pretty easy. Just click on the circle next to a book and one of the options on the dropdown menu will be to hide (or show) it.
This actually holds out an interesting possibility for library management. Since the online bookshelf contains copies of the books you've downloaded, you could use the online bookshelf as a manageable mirror of your on-device collection, in order to show a pared down selection of books. Let's say I've downloaded 70 books on my device and I've read 45 of them, so it's a little difficult to surf to the 25 I've not read. Well, I can hide all the books I've read on my online bookshelf, and thus have a list showing only the books I've yet to read. The only problem is that you need to be connected to the Internet to access the online bookshelf.