Locate rare, out-of-print, first edition and used books on sites such as Bookfinder.com and BookFinder4U.com. These online systems allow searches by author and title, along with additional options, such as searching for first edition and signed books or by ISBN.
Both Bookfinder.com and BookFinder4U.com have standard search features as well as extra options, such as publication year, price range and publisher. Alibris.com, by contrast, has a less fine-tuned search capability, but it also provides a database for movies and music as well as books.
One of the most powerful tools for finding a book is AddALL.com. It offers a metasearch capability across two dozen different book vendor systems, acting as an Internet search engine for those seeking specific books.