HARVARD — Kenneth Gloss, proprietor of the internationally known Brattle Book Shop in Boston’s Downtown Crossing section, will give a free talk Wednesday, Dec. 5 at 6:30 p.m. at Fruitlands Museum, 102 Prospect Hill Road. Gloss will discuss the value of old and rare books.

Gloss, a frequent guest appraiser on PBS’ Antiques Roadshow, will talk in part about the history of his historic bookshop, which goes back to circa 1825. He is a second-generation owner.

He will talk about and show some of his favorite finds and describe some of the joys of the “hunt,” as well as explain what makes a book go up in value.

There also will be question-and-answer session. Following, Gloss will give free verbal appraisals of all books that attendees have brought with them or will do so at his shop in Boston.