The following are the main sources for finding books in libraries.
The vast majority of books that are free online are published prior to 1923. Their U.S. copyright has expired and they are now in the public domain.
The following databases of ebooks contain older book titles. Each of the titles in these databases can be found in the AU Library Search. Access is limited to .
The advantage to searching each database versus the library's catalog is that one can search full text of every book in each database, not just the book record.