Barbara Kingsolver says that people often get her titles wrong. “Once a TV interviewer asked me how writing The Beans of Egypt, Maine has affected my life,” she recalls. “I was able to say honestly, ‘Not at all!’ ” That’s of course because the interviewer mistook Kingsolver’s 1988 novel The Bean Trees for a novel by Carolyn Chute.

No matter, Kingsolver has heard worse—like when someone referred to 1993’s Pigs in Heaven as Pigs in a Blanket. And though she’s good-humored about the errors, she is serious about titles. “Titles are very important to me,” she says. “I think of a title as a sort of skeleton key that unlocks a lot of different thematic doors inside the work. So it has to mean a lot of things. I always try to choose titles that have a lot of cognitive dissonance, words that knock against each other and rattle.”

Kingsolver’s newest book, coming in October from Harper, has a single-word title: Unsheltered. “The title on the contract was Unresolved, and that was its title for maybe four years,” she says. “A week before I turned in the manuscript, I learned that another widely read author was publishing a book with the same title.”

Fortunately, Kingsolver’s daughter Lily, a poet and environmental scientist, delivered the right word at the right time. “She said, ‘Mom, that’s it. Say the word and sit with it. Hear how edgy it is, how it has movement in it,’ ” Kingsolver says. “And she was right. I’m actually happier with this title. I considered acknowledging the famous author.”

In Unsheltered, two families in two centuries come to terms with great personal and societal change on the same property, located in Vineland, N.J. Several of the characters are historically real, including a naturalist named Mary Treat whose unconventional life as an unmarried woman in the 19th century inspired Kingsolver. “The title works for me because it has opposite meanings,” she says. “It’s unsheltered as in homeless, but also as in cagey. I intended both; Mary had to walk a careful line in living all those years without the shelter of a traditional marriage.”

Still, Kingsolver doesn’t want to be too obvious. “You want readers to connect the dots, and some people need dots to be very close together, and others don’t,” she says. “You don’t want to insult anyone’s intelligence by making things too clear.”

Kingsolver adds that she relies on her beta readers to help her stay understated. “I don’t want to be corny. I want, as part of the contract with the reader—to make them work a little bit to get to the riches. I want them to meet me halfway. But where is halfway?”

Over the course of Kingsolver’s career, that halfway mark has changed. Books like 2000’s Prodigal Summer alternate with books like 2009’s The Lacuna: the former is literary jogging compared to the latter’s all-terrain running. But even if a novel is serious and complicated, Kingsolver wants it to be readable. “I don’t buy the myth that it’s only great literature if only 17 people can understand it,” she says. “I want my books to be accessible to people who are committed readers but who don’t necessarily have a degree in literary criticism. And if they do? That’s just going to give my books an extra dimension.”

Kingsolver’s work, she insists, is for the reader. “It’s meant to bring something to readers’ lives, and that’s different for every reader. Each reader has different nutritional requirements—and nutritional requirements change throughout our lives.”

They change for writers, too. Kingsolver’s previous novel, Flight Behavior, published in 2012, was a contemporary look at climate change through the eyes of a young mother in Appalachia. Although its themes explored how the world is changing, its tone was less pointed than that of Unsheltered, which acknowledges how much information about our planet’s future has changed in just the last six years.

“In both halves of the novel, the main characters are dealing with a moment in history where everything they previously understood about life is proving to be not true,” Kingsolver says. “During the 19th century, Darwin and his colleagues were changing the very ideas of what it means to be human. Today, our belief in the American dream—that each generation has it better—has been shattered. We’ve kind of hit a dead end on having more. This isn’t a news flash from Barbara Kingsolver. This is the news. An economy that rests on permanent expansion has to hit a wall.”

Unsheltered is about how difficult it is to deal with a paradigm shift, for those alive during the industrial revolution and those alive during the computer age. “One of the things I really came to see for myself at a deeply emotional level while writing this book is that today’s problems can’t be solved by today’s people,” Kingsolver says. “They have to be solved by tomorrow’s people. Millennials see through the charade of our market because they’re already living with the fact that there won’t be a job at the end of the degree. There aren’t always more fish in the sea.”

Originally from Kentucky, Kingsolver now lives with her family on a working farm in Virginia, where they raise Icelandic sheep and all manner of vegetables. “This isn’t about choosing paper or plastic, or some vision of self-congratulatory parsimony,” she says. “It’s about replacing material gratifications with spiritual ones. I don’t know how much carbon I’m offsetting with my choices. I just prefer to be a good animal rather than one that fouls its nest. Also, and maybe most importantly, if I can learn to live happily with less, I feel more entitled to vote and agitate for legislation that would require everyone—even CEOs—to do the same.”

Kingsolver adds, “Anyone in my family would tell you that when I decide to do something, in life or on the page, I rarely give up. I like flying by the seat of my pants, because it feels so great when you arrive.” She says she feels most alive as a writer “when doing something I’m not sure I can do.”

Kingsolver wasn’t sure she could pull off Unsheltered, which, structurally, is two different novels, but its narration pulls it into one. “My challenge was how to link these two stories, beyond questions of theme or plot, and it was a lot of work,” she says. “I wanted readers to be able to open the book, read a sentence, and know exactly which century they were in from that sentence.”

For five years, Unsheltered was on Kingsolver’s back burner while she considered a few other ideas for books she thinks of as big (“not better, just more global,” she explains). She says she thought about writing a novel with Charles Darwin as a protagonist (“I love the man”) but ultimately believes “I am an American novelist who writes about American things.” She became interested in whom Darwin influenced on our shores. “I knew about [Harvard botanist and Darwin apologist] Asa Gray, but he didn’t float my boat. The magic was not happening with Asa; my research on him was like a really long bad date.”

However, while looking at materials on Gray, Kingsolver came across the name Mary Treat. “Almost nothing is written about her,” she notes. “Internet research turned up nothing except that a number of her books are available online, but nothing about her personal life. The only thing I learned was that she lived in Vineland, New Jersey.”

Kingsolver laughs and says, “New Jersey? I was going to do research in New Jersey? I thought, maybe I can turn up something useful at Vineland’s historical society. When I telephoned, there was silence, then a voice said ‘I’ve been waiting my whole life for this call.’ I got on a plane and just fell down a rabbit hole. Their amazing archive goes back to the town’s beginning in 1861, when a man named Charles Landis had the arrogance to found a so-called utopian town that, as part of its founding, included a historical society.”

What Kingsolver discovered was the kind of thing novelists dream of: a correspondence between the little-known Treat and Darwin. “This woman was going to be in my book—I knew right there and then,” she says. “She wasn’t bothered by what people thought of her. I’d had the big picture of this novel but not the right cast, and now I had my leading lady, if you will. Good things come to those who wait.”

Kingsolver knows she’s lucky to be in a position where she doesn’t have to sell any novel before its time. “I can take as long as I like to write a novel, and for the kind of novels I write, it can take a long time,” she says. “I’m grateful I could go to the Pine Barrens, because I fell for that place just as hard as Mary Treat did. I could imagine it 150 years ago. When one of the bog plants in my backyard pond—a pitcher plant just like one Mary might have examined—made it onto my book jacket, I said, ‘Look, you’re a cover girl!’ ”

Bethanne Patrick is a writer and book critic who lives in northern Virginia.