There are a number of popular Web sites that allow you to search by title, author or subject to find rare, first editions and even signed copies of some of the world's most valuable books. If you have your hands on what you believe to be a rare book, these Web sites can be a great resource for determining the approximate number of copies in circulation, as well as their selling prices.
The rare books section of AbeBooks.com is a great place to search for highly sought-after and expensive books. The advanced search option at AbeBooks.com not only lets you search by title, author, keyword, ISBN number and publisher, but also limits search results to certain price ranges, countries and special attributes like first editions and signed copies.
The "Search for Books" section of the Antiquarian Booksellers' Association of America Web site is another fine online resource for conducting a rare book search among the ABAA membership. To expand your search results to international booksellers, try the "Book Search" tab of the International League of Antiquarian Booksellers site.
The BiblioBot feature of the PBA Galleries Web site allows you to enter in all of the pertinent information about your book -- author, title, publishing year, condition, if it's a first edition or signed -- and receive an "instant appraisal." What the site really does is run a search on similar books for sale or auction and show you an estimated price range.
Of course, if you simply want to watch other people living out their "Antique Roadshow" fantasies, you can watch free, full-episode video clips at PBS.org.
For lots more information about books and fine art, see the links on the next page.