By 2005, when Brett Bonfield and Beth Filla bought a big old house near Knight Park, Collingswood's evolution from sleepy Camden County suburb to dynamic regional destination had begun.

So they rolled up their sleeves and helped move it along.

"Instantly, we loved living here," says Filla, owner and director of Yogawood, the popular yoga studio downtown.

"Collingswood has become such a cool hub," she adds. "And it keeps getting cooler and cooler."

Bonfield, since 2008 the director of the Collingswood Library, says the borough "has been a transformative place."

Now their own lives are about to be transformed: They're moving to Princeton. Bonfield was recruited to be director of that borough's library. He starts Jan. 19.

And while Filla will continue to own, and teach part time at, Yogawood, their departure surely is a loss for Collingswood.

"They're going to be missed," says Tom Marchetty, owner of the Factory, home to 15 small businesses in the former Collingswood Theater on Haddon Avenue.

Bonfield and Filla are taking leave of a thriving community that their intelligent, unpretentious, warm sort of cool has helped define for the last 10 years.

As a respected librarian and a successful Haddon Avenue businesswoman respectively, Bonfield and Filla have blended in with old Collingswood. They've embraced the borough's many block parties and parades and holiday events.

But they've also been prominent among the wave of newcomers bringing fresh energy and a welcome dash of diversity to the borough.

"Brett and Beth have left their mark," Mayor Jim Maley says.

"I think of them as a power couple. They're so good at connecting people," says Rachelle Daminger, who teaches at Yogawood, which she describes as "a special community" that reflects Filla's qualities of kindness and openness.

Adds Alice Marks, president of the Collingswood Library's board of trustees, "Brett has been a great library director, responsive to the needs of the community.

"When there was a need for more meeting space, he created it out of an unused area on the second floor," Marks adds. "He planned dances at the community center as fund-raisers for the library."

I catch up with Filla and Bonfield at their apartment above Yogawood. They bought the building last year after selling the house near the park and moving Yogawood from its debut location a few blocks west.

Theirs is a stylishly welcoming space on the east end of the Haddon Avenue strip, where a mix of fine dining and funky retail has put the borough on the map.

"We're been here for a lot of the recognition that Collingswood has gotten," says Bonfield, who, like Filla, is 45. "We've gotten to really enjoy it, and contribute a bit. We're part of the zeitgeist."

When they arrived, the borough already had the volunteerism, well-attended community events, and other forms of civic capital that have long been a strength.

But "things were right for a change," notes Filla, who along with a former business partner opened Yogawood in 2006.

"As soon as we hung the sign, people were responding," Filla recalls. "It was immediately well received."

Bonfield grew up in Abington, and Filla grew up in Collingswood. They met in the mid-1990s, and married in 1998.

Both worked for nonprofits, and each went on to earn a master's degree, Filla in social work from the University of Pennsylvania, Bonfield in library science from Drexel University.

"Neither one of us ever wants to hold the other back, personally or professionally," Filla says, noting that she became primary breadwinner earlier in their marriage while her husband wrote novels.

In turn, "Brett stayed in a job that was not the best fit for him so I could pursue my master's," she says.

"So when he was recruited for the Princeton job, we talked about it while we were sitting in the hammock on our back deck."

"And she said, 'Maybe you should consider it.' " says Bonfield.

So they headed up I-295 for a field trip to Princeton.

"It has a lot of the same feel as Collingswood," he says. "It's not a huge place, and it's a community where people care about each other and the world."

Filla points out that she'll be in Collingswood a couple of days a week to teach. Bonfield says he'll take her classes and return to shop in the Collingswood Farmers Market next summer.

"Collingswood is a great, great place to live," Filla says. "I'm glad we get to come back."

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