The event attracts thousands of people from across New England and is the library's biggest fundraiser of the year.
Organizers say they have more than 60,000 books for sale, as well as CDs and DVDs, including some rare finds.
"We have one extremely rare book -- it's one of nine original copies of "Crime and Punishment" -- the first printing in English. One sold at auction, the most recent one that sold at auction sold for $18,000 and we were fortunate. It just came into our book bin, so we are offering that as well," said Doug Fried, chairman of the Pequot Library book sale.
The sale runs through July 25.