When Kathy Burns Rosen found the letters in a trunk in her mother’s attic stacked on top of her old college keepsakes, she sat down and her eyes filled with tears.

Only one thought ran through her mind — she hadn’t kept her promise.

Rosen picked up the letters, yellow with age, and went through them one by one. In children’s penmanship, most of them were addressed in pencil. Some had zip codes included. A few of them had simple flowers drawn on the back.

Each of the envelopes had “please forward” scrawled across the front. And they still were all sealed.

As she looked them over, she remembered each small face of the 25 Sunset Elementary fifth- and sixth-graders she taught her first year out of college in 1970.

She had asked her students to write a letter to themselves describing how they would like the world or their lives to be in 10 years. In preparation for the assignment, the class talked about Vietnam, the anti-war movement, social unrest and what those movements said about the country.

“I told them, ‘Write a letter, and I promise, I’ll mail them back to you in 1980,’ when they’d be about 21 or 22 years old,” recalled Rosen, who is now on a quest to keep her promise and find each of her students to return their letters. “They put their hearts into those letters.”

After she taught at Sunset Elementary in Bellevue for a year, she moved to eastern Kentucky and taught in a middle school and then on to New York where she worked with inner-city families. Ten years rolled by and she was just busy with life, had gotten married and eventually had a son.

Nearly 40 years later, Rosen found the letters last year and felt heartsick. She brought them home with her to Florida and put them on a shelf.

“Every day I would look at the letters and would feel worse and worse,” she said over the phone from her Fort Lauderdale home. “I felt overwhelmed by guilt.”

When January came around, she realized her “kids” would be turning 50. That’s when she decided she could wait no longer.

A couple weeks ago, she started with online searches and sent out letters to local and national news and radio stations. She even wrote the Oprah Winfrey Show.

She also contacted the Bellevue School District, but there were privacy issues involved and they would have had to go back and look through microfiche.

“I feel as though I’m a detective and on this great case and I’m going to crack it,” said Rosen, who students knew as “Ms. Burns.” “I’m going to work on this as long as it takes.”

The first student who contacted Rosen once he heard about her mission is now an American Airlines pilot. He helped put Rosen in touch with another student.

She was on the KFBK Sacramento radio show when they had taken a break.

“I went in to check my e-mail and there was this student who said, ‘I’m listening to you right now!’” Rosen said.

The radio host got her and student, Steve Waiss, on the phone and on live radio.

Waiss, who lives in Renton with his wife and three kids and is an insurance agent, has often wondered what happened to his letter over the years.

He recently received it in the mail and laughed at what he had written.

“I thought we had put down what we thought we would be doing in the future and what career we would have,” Waiss recalled. “I just got my letter, and the assignment didn’t have anything to do with that.”

When Waiss opened his letter, it turned out that the question was what he thought would have the biggest impact on the next decade.

His answer?

The Supersonic Transport – the jet that The Boeing Company worked on, but was never developed. He had gotten the inspiration for his answer from his dad, who worked for Boeing.

“I think it’s really neat she has the passion to follow through with her promise to her students,” Waiss said.

Kim Walter Cameron, a project manager for Boeing who lives in Sammamish, received a surprise last week when she heard her fifth-grade teacher’s voice on her answering machine.

“I remembered her instantly,” Cameron said.

Though she can’t remember writing the letter, she said she can’t wait to get it in the mail and see what she wrote all those years ago.

So far, Rosen has tracked down almost a third of her kids. Each time she mails out another letter, she’s happy, even though it’s hard letting go.

She hopes that once she finds all of her students that they will be able to have a reunion in their old classroom.

“This whole process is such a gift,” she added. “Of course kids get their letter – they might be profound, might be trite, who knows – they get their letters and I get the joy of having them in my life again.”