Kristin McGlothlin has vivid memories of being a young teen, filled with a sense of purpose and possibility. “When I was the same age as my characters, 13, I remember sitting in my backyard in a chair,” she says, and “characters started coming into my head.” It wasn’t until years later that she brought some of those long-ago characters to life in her Sourland Mountain series.

“I like the age,” McGlothlin says, explaining why her characters are young teens like she was at that pivotal moment. “I remember that time, feeling secure in my curiosity and wanting to learn and not worrying about things.” River Wren, the protagonist of Country of the Birch Trees, the third book in the series, pursues her curiosity about art and her family’s cultural background. 

Along with her friends George and Joe, River forms a detective club to investigate the everyday mysteries they encounter. River wants to learn more about her Lenni Lenape heritage, but her Lenape father doesn’t want to discuss his family, so she does her own research:

What she thought of now as her dad’s book didn’t have a lot of information in it about the tribe. It had beautiful watercolor illustrations portraying families working together to construct shelters and to prepare a deer to use for food and clothing. The text explained what was obviously shown in the pictures. The book was a little disappointing to River because it didn’t show or tell her anything different from what she’d seen and heard in school. What was magical about it was that it had been given to her dad when he was an infant. She was thankful for her dad, as well as the rest of her family and her friends. 

“The author deftly handles complex issues, like cultural background and mental health, in a gentle but realistic manner,” concludes the Kirkus reviewer, who also calls the book “a sweet, positive tale.” Country of the Birch Trees follows Drawing With Whitman and Listen, about other children in the same New Jersey community, which means the books can be read in sequence or as stand-alones.

In the third book, River comes from a family of artists—her father is in a heavy metal band called Beowulf’s Brother, while her mother is a potter who sells her ceramics at a local market. Art has always been important to McGlothlin, whose previous career was in the field. 

“I worked really hard to get the job I wanted in an art museum, and it turned out not to be the job I wanted it to be,” she says. Her position dealt with education and programming, which left little room for her to engage creatively with art. After several years, she decided to go back to school and pursue a different career path. “I remembered when I was a kid, I had this idea that I wanted to write,” she says, so she completed a master’s degree in English.

McGlothlin doesn’t generally read middle-grade books—she wants to avoid absorbing other works into her own writing, and she currently prefers reading mysteries for fun, especially Agatha Christie. But she does have a soft spot for middle-grade novels of the 1960s and 1970s, with Louise Fitzhugh’s The Long Secret a particular favorite. “The characters live in a safe environment where they’re allowed to feel uncertainty about their surroundings, about adults, about things they may see their parents do that they’re confused about,” she says. “The kids are allowed to explore issues that are very important and serious, but they’re not portrayed in a scary way.” 

The combination of a sense of safety and a willingness to touch on somewhat dark topics is the approach McGlothlin brings to her books, which address topics like depression and parental abandonment but do so in a world where communities come together and teens form detective clubs. 

“I have been writing full time for the last three years,” McGlothlin says, and writing the Sourland Mountain books has been a process of learning and developing her craft. “Writing a book is hard. If anyone tells you it’s not, I don’t know what they’re doing.” She credits her editor with helping her bring the first book from manuscript to final product, sharing lessons about structure and streamlining that McGlothlin implemented when she started outlining the second book, which allowed her to be much more focused on the story.

McGlothlin has planned out four books in the Sourland Mountain series plus a second series featuring the same characters. The first book in the second series will be set in Egypt, taking the characters “outside of their little world” for the first time. McGlothlin recently traveled to Egypt herself, and she used the trip to prepare for writing the book: “I journaled every day. I journaled in the mind of my new character.”

Although the geographic scope of the books will expand and the timeline will shift, with some of the current child characters appearing as adults in later books, art will continue to be an important part of each storyline. “I wanted to show my art background in each one,” she says. In the books, McGlothlin writes about how art can “help the kids deal with the issues in their families,” and she encourages readers to try making their own art.

One of McGlothlin’s favorite genres is earth art, which she calls the “type of art that anyone can do—just go outside and find some leaves, anything in nature, and make art out of it.” She cites Andy Goldsworthy as one of her favorite artists in the field, but she also says that earth art is welcoming to amateurs, “a great place to start if you haven’t made art in a while.” McGlothlin believes art is a basic human instinct and a powerful source of connection, a theme that runs throughout the Sourland Mountain books. 

Sarah Rettger is a writer and bookseller in Massachusetts.