Find out how much that old dust-collecting book on your shelf could be worth. You may not have a use for it, but if it is worth some money, someone may be willing to pay to take it off your hands. Collectors would more likely be interested and even if it isn't worth very much, you could still sell it or give it away. Here's how to determine the value of the book so you can decide on the next step.
Purchase a "Pricing Guide" book. You can find one of these online or even at a local bookstore, maybe a local library. A popular pricing guide for book value is "Fadedgiant Guide." The website of this guide also contains over 50,000 antique book prices. If your books are newer, say the past 10 years at least, you might still look to see if they have any prices listed. They also provide useful information for if and when you decide to sell your valuable books.
Consult a professional. If you aren't confident that you can really define the value of the book by yourself, meet with a professional book appraiser. You can do a search on the site listed in the reference links below that will help you locate a local appraiser. You may have a friend that could recommend one for you as well, so be sure to ask around.
Do some research. You may be able to figure out the value of your book with minimal effort. If the author is quite popular, you already have a chance of it being worth something. Another factor that will increase the book's value is the amount of those books published. The date of publication of the book will also play a rather important role in the value. Do some research online to see if you can't find the value of your books.
Evaluate your book. If the author is someone like William Shakespeare or Agatha Christie, you are already aware it will be worth something. If you own a book that is a first edition it will definitely have some value. The book will need to be unique in order to have a high value, so if it is signed or autographed or it is no longer in print, you probably have a very valuable book on your hands.
Make sure you pay close attention to the book's condition. Note if there are any tears, earmarked pages, scuffs, loose binding or anything that could affect the value of the book.