Elayne Perlstein, 90, is the sole librarian at the South Chatham Public Library, keeping the non-profit library open two afternoons a week year-round.

On a sunny Friday afternoon in late August, Perlstein, who describes herself as “a people person,” greets a visitor warmly, but too many patrons are waiting to check out books to chat now. A few days later, at the West Chatham Dunkin’ Donuts, she has the leisure to talk about her life and the library where she has been employed for 14 years.

Perlstein was born in Swampscott and lived in Winthrop before her marriage to Fred Perlstein. She and Fred raised their son and daughter in the Hartford area where Perlstein worked as an insurance analyst with Connecticut Mutual. But not living near ocean, “I missed the water terribly.” So she and Fred found a small house in Harwich Port and they would drive down every weekend. Eventually they bought a larger house for their retirement in South Chatham.

After she retired in 1983, Perlstein volunteered at the American Cancer Society in Hartford. She was put in charge of the Daffodil Days program and raised funds in the six figures. And at her 25-year mark she received an award. “I gave it my all,” she says.

She and Fred moved to Chatham year-round in 1996 after Fred retired as vice president of advertising at Ames Department Store. An avid reader, Perlstein soon wandered into the South Chatham Public Library, established in 1934. Today the library is in a one-room building owned by the South Chatham Community Church on the corner of Main Street and Mill Creek Road. When Perlstein first visited it, it was run by Helen Warren. “She took to me,” Perlstein says, and Perlstein began doing small tasks for Warren.

After Warren’s death in 2005, “I got a phone call from the president of the board of the library,” Perlstein says. He invited her to sign on as the new librarian, a job she readily accepted.

“I love the people who come in,” she says. “They’re nice to me and I’m nice to them. It’s a good relationship that we have.” She is, in fact, so close to her patrons that when she learns a grandchild is on the way she will often knit an afghan for the newborn’s carriage.

Since the library is not a part of the Cape-wide CLAMS system, Perlstein is free to run it by different rules. The check-out period is two weeks, but she does not collect fines for overdue books. In fact, she has established something of an honor system.

While with popular books she tells people to make every effort to return the books by the due date, she’s not strict about the due dates on older books.

“If you’re in a book that you don’t want to stop reading, I don’t care, keep it,” she says. “I don’t think you enjoy your book if you have to read it by a certain date.”

Perlstein herself acts as the library’s book buyer.

“I can tell for my readers what books they would like,” she says. She’ll buy 30 new books a month in the season and, unlike patrons in the CLAMS system, Perlstein’s patrons do not have to wait days or weeks for a popular selection – a tremendous perk.

“You’re darn tootin’,” she agrees.

While the library has no children’s department, it does carry some picture books for pre-school children, shelved low.

The library holds an annual book sale, which is necessary due to the small building that holds more than 3,000 books. Which books are culled out and sold is at Perlstein’s discretion. She looks at the due dates that she has stamped into the backs of books (the library has no computer system), and determines that a given book is no longer circulating. That book will go to the sale.

Who can check books out of the library? Anyone, it turns out. Patrons fill out their name, address and telephone number on an index card. And that’s it.

On her days off, Perlstein volunteers at the Brooks Free Library in Harwich.

“Some of the nicest people work in libraries,” she says.

What does Perlstein herself read? She loves mysteries, in particular Michael Connelly and David Baldacci’s crime series. She used to love John LeCarre, but like many of his fans, she feels his recent books have lost the charm of the earlier ones. She follows mystery writers Louise Penny and Jacqueline Winspear.

“I get the books first but I do not read them first,” she says. “I can’t do that. People are waiting.”

Perlstein’s entire family, including her five grandchildren, came to Chatham to celebrate her birthday last month. Her library patrons also marked the event by giving her a cake.

Does she have plans to retire?

“No, I don’t,” she says, laughing. “Even at 90. I do not, I do not. I don’t think they want to get rid of me, they know I’m pretty good.”

South Chatham Public Library is at 2559 Main St. Hours are Tuesday and Friday from 1 to 4 p.m. Contact the library at 508-430-7989 for more information.