Are the books on your shelf worth anything? Find out at a free workshop at the Mattapoisett Library on Sunday, Sept. 18 from 2 to 3 p.m.

In the style of PBS’s The Antiques Roadshow, Ray Rickman, long-time rare book dealer and former bookstore owner, will offer complimentary estimates for up to three books per attendee.

Learn from Rickman’s extensive knowledge as he answers questions such as “What determines a book’s value?” and “How and why does this value change over time?”

This program is free and open to the public, but register by calling 508-758-4171 or emailing rsmith@sailsinc.org. Provide the number of people attending and contact information.

The library is located at 7 Barstow St. and is handicapped accessible.