"My mom's like, 'Did you know that David wrote a book?' I didn't even know he was working on one," Walberg said.
From 2008 to 2011, Hartness, 33, served in the Peace Corps in Namaacha, a city 45 minutes outside of Mozambique's capital. He said that during that time he learned about the violence and conflicts that overtook the Southern Africa coastal country from the 1960s to 1992.
"You'd walk down the street and see what used to be very beautiful Portuguese structures with bullet holes in them," he said, "and then you would listen to some of the older people who would talk about what that meant to the country, and upon leaving Mozambique I realized that there was a story there that very few people knew."
After researching and looking at footage of Mozambique's civil war, Hartness found that children had been recruited into the conflict and were used to commit acts of violence.
"I felt there was a story where I could link a modern-day issue, with Boko Haram and ISIS and other organizations who also recruit children to fight in battles, with the historical perspective that I wanted to teach people," he said. "I wanted to make some change in the way people think about wars and how we use children, and about what we can do as a society to ensure that guns are not being put into the hands of children, and that we are doing something to ensure that children get the education that they need and not [be] exploited in this manner."
Around the same time that Hartness was researching the history of Mozambique, Walberg said she was in Laurel watching news coverage of Hurricane Sandy battering New York.
"I was watching as the island that I lived on went completely underwater. There was no ground," she said. "I couldn't imagine how scary that was."
Walberg, 50, had just moved back to Laurel after finishing up a contract at St. John's Episcopal Hospital in Far Rockaway, N.Y., where she worked as a compliance officer. She said that in her career as a health care consultant she had never before seen such an impoverished hospital.
"It was a tough job. Every time you fixed one thing there were like 10 more broken things," she said. "The thing that got back to me about that place was that the people there were so dedicated, and they were up there through the whole Hurricane Sandy thing, and it really affected me. I thought, these people are something else."
The hospital stayed open during Hurricane Sandy to accommodate evacuees and care for patients.
"To me it was a horrific story, and I really felt ... I've always wanted to write, but I never had the motivation," she said. "But this story was a story I thought should be out there. I know people up there who have been through everything."
The National Oceanic and Atmospheric Administration estimates damage caused by Sandy in the United States at $71.4 billion, making it the second-costliest storm on record after Hurricane Katrina.
Walberg wrote her book "Finding Maslow," which was released in September, in the six months following Hurricane Sandy. Hartness wrote his novel in 30 days and took two years to edit and several more to research it. "Amani's River" was released in January and is a finalist for a National Indie Excellence Award.
On Friday, from 5 to 7 p.m., the two authors will sign copies of their books at Oliver's Old Towne Tavern on Main Street in Laurel.
"I had an epiphany one day: When my book comes out, we should do a launch party together and raise awareness about these issues," Walberg said. "Oliver's is a nice place for the Laurel community to get together, so I thought it would be great for this event."
Hartness moved into Walberg's home in Old Town Laurel in August after living in Africa for almost eight years. He wanted to move back because his son, Lucas, whom he adopted from Mozambique, plans to attend college in the United States. Lucas is currently a freshman at Laurel High School.
"I knew that we had to re-establish ourselves in the States, and I thought that the transition would be easier as Luc entered high school," Hartness said.
When Walberg found out that Hartness wanted to move back to the United States, she suggested that he and his son move into her house in Laurel. She thought that Washington, D.C. would have the best job prospects for Hartness, given his international experience and interests.
"I want to work for a nonprofit organization, where I can not only continue developing educational initiatives, but also hopefully develop African initiatives," Hartness said. "So much of the [non-governmental organization] world happens here. I thought that it would be a great opportunity for me to get my feet on the ground and really start to dive into that world. And of course having Susan here to help transition made it a lot easier for myself and my son."
Walberg also has an adopted son, Dmitry, who is 16 and lives in Seattle with his father.
"When I was younger, a lot of kids from Asia were coming over here and getting adopted," Walberg said. "I saw this on the news and asked my mom, 'Why can't we do that?' She couldn't at that time, but that stuck with me, and as I got older, I educated myself in Russian literature and became enthralled with Russian culture and people."
Walberg and her ex-husband adopted Dmitry from Russia when he was 7.
"My son and I are going to write a book together about adoption," she said. "When he found out about this book, Dmitry said he wanted to write book, too. He has already started writing his."
Hartness and Walberg, whose mothers are cousins, both grew up in Washington state not far from one another. But they did not become close until their families started going on camping trips together when Hartness was 13 and Walberg was 30.
"We would stay up after everyone else had gone to bed and talk around the campfire," Walberg said. "We just clicked."
Then the two cousins, who said they were the oddballs in their families, started camping on their own.
"Most people didn't think we'd come back alive," said Hartness.
"I used to tease him that he was the other dumb blonde in the family," said Walberg. "He was the one who took his cologne on camping trips."
When she first found out that Hartness joined the Peace Corps, she said, "Wow, Gucci boy went to Africa?"
Now that Hartness is back in the States and living in Laurel, Walberg is excited that they can market their books together.