1. "Catalog" tab to the Duke Libraries catalog
Here are some subject examples of what you can find:
Worldcat - combined catalog of all libraries
Use Worldcat to locate exhibition catalogs and books for interlibrary loan and archives of collections. There's a "libraries with this item" link that shows NC libraries first.
Virtual Catalogue for Art History (www.artlibraries.net) - consortial catalog of the large specialty art libraries (mostly art museums libraries), including Met, MoMA, and major foreign institutions. Helpful because subject is only art(s); interlibrary-loan is not possible, but this catalog confirms the existence of items possibly obtainable through other methods.