A passerby spotting the long line stretching down Mott Avenue in Far Rockaway early on the morning of May 31 might have assumed a celebrity was in town or a new electronic gadget was on sale. But the people who queued up on a Saturday morning outside the Refuge Church of Christ were there for something else: 40,000 free books.

The book giveaway was the result of a partnership between the UFT, the American Federation of Teachers and the nonprofit organization First Book, with the help of the A. Philip Randolph Institute, the Coalition of Black Trade Unionists, the Coalition of Labor Union Women and the Labor Council for Latin American Advancement.

“The excitement as children pick out their own books is contagious,” said UFT President Michael Mulgrew, who welcomed teachers, parents and children to the event. “Give a child a book — especially one that they chose themselves — and you have put them on the path to being lifelong readers.”

The organizer of the event, Anthony Harmon, the UFT director of community and parent outreach and the president of the A. Philip Randolph Institute, said the event was a way to help a community still recovering from the devastation of Hurricane Sandy in 2012.

Volunteers from the UFT, the AFT, other labor unions and churches unpacked and sorted the books, which were shipped to the church in a 53-foot tractor-trailer the previous day.

People started lining up before 8 a.m. on Saturday, and by the time the gates opened at 11 a.m., the line stretched down the block and around the corner.

“I got here early, just in case,” said Dorothy Martin, 67, the first person in line. “I am here to find books for my 6-year-old great-granddaughter, my 21-year-old granddaughter and for myself, if there are any for someone as old as I am,” she added with a laugh.

Seventh-grade teacher Christina Vowinkel gathered a suitcase full of books for her classroom library at the Young Women’s Leadership School of Astoria.

“I always need new books for my students, and multiple copies, so they can have book clubs and talk about what they read,” Vowinkel said. “This is just wonderful.”

The same number of books was given away at a similar event last year in the Bronx, which drew hundreds of teachers, parents and children.