After processing and marketing over 25,000 books in the past ten years, we are still challenged on the issue of determining whether and to what degree a signature or hand-written inscription in a book impacts value and marketability. It is also one of the most commonly asked questions when we make presentations at libraries and other venues on valuing and selling personal collections. So we have given the matter a lot of thought. While not definitive by any stretch, here is our view on the subject.
There are basically two types of signatures and/or inscriptions found in books. The first is by the author, illustrator or other party directly associated with the production of the book. The second is by someone not directly related to the book. It goes without saying that the fame or infamy of the person whose signature is in the book is the largest single determinant of value and that value is obviously directly related to the level of fame they possess. If you have any doubt about whether the signature is of a noted personage, the best litmus test is to see whether they are listed in Wikipedia. If not, then the value of their signature may be marginal except perhaps in narrow circles, where the signature is of someone well known in a small circle of acquaintances, like a professor they had in college.
A related consideration is how common the signature might be. Some authors have extensive book signings. Others sign very view. The less the better. It also helps if they happen to be dead, as that pretty much closes off any more book signings.
Inscribed books by authors or illustrators present a more complex situation as there are at least two parties to consider. Ordinarily, books that are flat-signed by the author, or where a general inscription is written without naming the recipient, are more valuable that books that are inscribed. The exception is where the recipient is also a well- known personage. These are often called “presentation” copies and can increase the value of the book significantly depending on the parties involved.
If, however, the recipient is an ordinary Joe or Jane, then it is likely to be less valuable than a flat-signed signature by the same person. An exception is where the inscription involves something extra, like a doodle by a famed illustrator. The doodle itself adds value to counteract the fact that it is inscribed to a nobody.
The best way to determine what impact the signed/inscribed book you have on its overall value is to go to Abebooks.com. It contains a toggle that allows you to filter out books that are not signed/inscribed. Comparing the filtered and unfiltered list goes a long way in specifying any enhanced value the signature/inscription might have. You can then read the descriptions of the signed/inscribed books to see if any of them come close to what you have in hand.
The same considerations apply to books signed by their owners or inscribed to a current or former owner. If the signature is of someone who is famous, it generally enhances the value of the book even though that individual is not directly associated with it or only marginally so beyond giving it away.
In general, however, a signed/inscribed book by a nobody given to a nobody, diminishes the value of the book by one quality level. In other words, if the book, unmarked, is rated in “As New” or “Fine” condition, the book marked by a signature or gift inscription, is likely to be downgraded to “Very Good, and priced accordingly. This is certainly true for newer books.
For vintage or antique books, where both the donor and the recipient are long gone from this Earth, the change in value is generally not material. This is because back in the day it was a common practice to sign, or otherwise assert ownership over, a book by something like a stamp or bookplate. Some of these signatures and inscriptions can be quite beautiful and can be seen as an integral part of the provenance of the book. The same goes for signed bookplates. These things don’t impact value much but might enhance or diminish marketability slightly depending on what the buyer is looking for or will tolerate in the book they are looking to acquire.
Author: William D. Adams