The Grimm Legacy by Polly Shulman (2010)

Charming young adult novel about Elizabeth, who gets a job as a page at the New-York Circulating Material Repository, which lends out objects rather than books. It's also home to the Grimm collection, which contains magical objects that inspired the famous fairy tales. When items (and pages) start disappearing, Elizabeth and her fellow pages have to use everything they can to solve the mystery and get them back. This book is fabulous for anyone who loves libraries and fairy tales. It's subtle and charming, mysterious and romantic and a little funny. Great characters. So yay!  Shulman also wrote the witty young adult Pride and Prejudice-inspired Enthusiam.