NEW YORK >> For months, the Strand bookstore in downtown Manhattan, from its fiction stacks to its cookbook section to its rare books, has been nearly deserted. But Sunday, half an hour before the store was scheduled to open, about a dozen people lined up in the cool fall breeze, waiting to get inside.

They had come in response to a plea from the store’s owner, Nancy Bass Wyden, who announced on social media Friday that its revenue was down nearly 70% from last year and that the business had become unsustainable. “I’m going to pull out all the stops to keep sharing our mutual love of the printed word,” she wrote. “But for the first time in the Strand’s 93-year history, we need to mobilize the community to buy from us so we can keep our doors open until there is a vaccine.”

The Strand’s legacy has not been without complications, and Wyden has a tense relationship with the union that represents her employees. But it is a New York City institution, a throwback to a quirkier type of local retail, and many New Yorkers were unwilling to let it go down without a fight.

“I really couldn’t believe to see that such a big piece of New York culture is struggling,” said Victoria Pompa, 23, who came from Staten Island with her parents after seeing a post from the store on Instagram. “So we just wanted to come and show our support.”

Wyden said the call for help produced a boom in business Saturday: a single-day record of 10,000 online orders, so many that the website crashed. That day was also the best single day in the month of October that the flagship store, near Union Square, has ever had, and the best day ever at the Strand’s Upper West Side branch, which opened earlier this year. In the 48 hours since the plea went out, the store processed 25,000 online orders, compared with about 600 in a typical two-day period.

One of them was a purchase of 197 books from a customer in the Bronx. “I’ll have to write her a thank you letter,” Wyden said.

Wyden said that employees have canceled vacations and were coming in on days off to help with the surge.

“We’re optimistic,” said Laura Ravo, the Strand’s new chief operating officer. “We asked for a lot of love, and we received a lot of love, both in store and online, and on social.”

With millions of people largely stuck at home, book sales are up this year. But much of that shopping is happening online, and independent bookstores across the United States have rushed to reinvent themselves even as they watched their sales crater. The American Booksellers Association said this month that more than one independent bookstore has closed every week since the pandemic began.

Among the stores struggling most are the larger independents, which have higher expenses for space and staffing and need more sales to keep going. They also tend to be more reliant on events like readings and signings for their revenue. The Strand usually hosts about 400 events a year.

In their place, the store has done online readings and is experimenting with offerings like a Book of the Month program and boxes of “book hookup” surprise titles, which are grouped by genre. The store is also providing private guided tours of its rare books collection, a staff expert to curate and stock home libraries, and “books by the foot” sold as decorative space filler in the new era of bookshelves as Zoom backdrops.

Still, when Wyden saw the store’s receipts for September — a month in which she had expected business to rebound as students returned to school and some businesses reopened — she said she realized that those initiatives weren’t enough. She decided to make a direct appeal to customers.

“People tell me all the time that this is their favorite place,” she said. “They seem to always have a Strand story. I met somebody at a cocktail party, and she told me about getting engaged in the rare book room. Two people came in yesterday; this was their first date.”

Wyden’s relationship with the union has been less romantic, with allegations of contract violations and union busting going back for years, said Melissa Guzy, a shop steward in the Strand’s art department. This summer, employees protested outside the stores, saying that Wyden had laid off most of its employees despite receiving a Payroll Protection Program loan to retain 212 jobs.

The union also criticized Wyden for buying stock this year in Amazon, a company that is despised in the indie bookstore world. Wyden has said it was a way to generate money that could be put back into the store.

“Really, sustaining the stores, it’s been a marathon with no end in sight,” Wyden said. “So we really had to be careful with the PPP loan money.”

Guzy said that despite their disagreements, she still hoped the store would survive.

“When people support the Strand, they aren’t just supporting Nancy; they’re supporting us; they’re supporting the workers,” Guzy said.

There were no demonstrators outside the flagship store Sunday, just a steady stream of customers in a line stretching around the block. Many, like Dan Bressner and Kaitlin Kwiatkowski of Manhattan, who were shopping together, said they had heard about the store’s plea for help and about its labor dispute.

“It’s awkward because the track record for the ownership here is not great,” Bressner said. “But it’s also an institution. My parents shopped here.”

Kwiatkowski agreed, and she bought three books that day. “We’ve got to do our small part,” she said.