So, danish libraries are purchasing robots to handle book returns. These robots only do coarsegrained handling, since bookshelves are a little to delicate for robot fingers at the moment. However work is under way in labs at Johns Hopkins and University Jaume I in Spain. At Sonoma State University, they solved the problem by making the library storage room more robot friendly (vendor, Wired story)
Library Journal has a story of just one library that's shipping 50000 volumes per day to patrons, and obviously needs Amazon style automation to do it. The same automation is available in a home edition on the Mac.