Use the following tools to get books from other libraries:
These catalogs search the holdings of major art libraries around the world. Best when its useful to limit the scope of your search to just items related to art history.
Google Books and Hathi Trust let you search through the entire text of books and are very useful to finding mentions of specific topics.
The Art & Architecture Collection is arranged in Library of Congress call number order, and can be found in the northwest corner of the second floor. Relevant call number ranges include:
Not sure where to find the book you need? Check out the map of the Art & Architecture Collection.