I couldn't resist a book about a teenage library page ... especially since she's working at a materials repository (rather than a book repository) that has a collection of magical items collected by those famous Grimm Brothers!
I *loved* this book: It's got suspense, magic, mystery and lots of the unexpected. I absolutely did NOT know what would happen next, or how - and that's really rare. I anxiously read along, wondering upon wondering what would happen next and who would be behind the strange happenings in Elizabeth's library.
Although it's positioned as a teen book, there's no reason middle schoolers or even mature readers younger than that wouldn't enjoy it too; there's no gore, only a bit of chaste teen romance, and a plot that moves things right along.
I can't find anywhere that says it's the first in a series, but I hope it is. And I can see how it might be!