Dear Mary: I had the address of a Web site that allows you to list your books by ISBN and swap them with other members. My plan was to let my daughter enter all of our books into the system so she would have an allowance for her book purchases. Unfortunately, I have been unable to find that Web site again. Can you help? — Echo W., e-mail

Dear Echo: The site you are looking for is PaperBackSwap.com. Your daughter can enjoy trading paperbacks, hardbacks, audio books and textbooks. The site is fantastic, with search features, reader reviews and ratings, similar to Amazon.com and www.bn.com. More than 4 million books are listed at PaperBackSwap.com. Membership to the site is "currently free for charter members," which leads me to believe the site will be instituting a membership fee in the near future. I would sign up quickly.