One of the great benefits of the internet to book lovers is that they can now determine the market value of a book by consulting online bookstores. They can also consult book price comparison services to see at a glance what several bookstores are asking for precisely the same book.

Often people come to our brick and mortar used-book shop asking the value of a certain book. In most cases it turns out to be much less valuable, in monetary terms, than the person had supposed. Often the book-owner confuses the sentimental value of the book (my great-aunt Molly left it to me) with the price that the market may be willing to pay for that particular book. Where the sentimental value is high, the monetary value is invariably low.

Before the explosion of online book dealing, which began around 1994, determining the real value of a book was a headache. One ended up phoning experts for price guidelines or wading through printed catalogues or else just using one's gut feel. Now it is possible with the click of a mouse to see where a book fits into the book price universe.

The method of using online bookstores to value books is in fact how secondhand bookstores determine whether it is worth buying a book. When confronted with an old leather-bound volume, for instance, and asked to make an offer for it, the book dealer will in all likelihood head for the PC.

If there are only a couple of copies of identical books (in terms of edition and condition) in the online bookstore and the lowest priced of them has a high price (anything above $20), then it may be worth the dealer's while for her to offer to buy the book. She would then mark it up to the lowest listed price or even lower. The book dealer may or may not list the book for sale on the internet, but even if the book is put on the shelves in a secondhand bookshop in the mall, then the bookshop owner has the satisfaction of knowing she is not ripping off the public or doing herself down either.

It is important to note that the listed prices of books in internet bookstores are asking prices only. There is no comprehensive database yet, of book prices that have been realized. It is fair to assume though, that as the number of books available for sale in online bookstores approaches the one billion mark, the more authoritative and accurate the aggregate prices for listed books are becoming. The sheer weight of numbers is also showing up those online bookstores, or individual booksellers on group sites, whose prices are unrealistically high.

All this data can never take into account the subjective reasons for which people so often buy books. These include the smell of the pages, a memory of this book in someone's house, a half-recalled phrase, an arresting illustration, the feel of well-worn boards. These emotional feel-good factors may persuade buyers to purchase a book, even at a premium price. Most of these things can be appreciated by buyers only in a walk-in bookstore, where they can browse at leisure and in peace.

The internet book store can never replace the experience of browsing and its emotional responses. The smart book dealer in the brick and mortar store should take this into account and factor it into the price of her books.