For readers reluctant to read about science, author Mary Roach is like a gateway drug. The focus of Roach’s seventh book, Grunt: The Curious Science of Humans at War, is the science of the human body, and she approaches her craft with a curious mind and a humorous bent, translating high science into a highly enjoyable read. Grunt, out in June from Norton, looks at the scientists who are diligently keeping human beings alive, safe, and even comfortable through the difficulties of war.

Roach, 57, lives and works in Oakland, Calif., but she was born in Hanover, N.H., and grew up in the nearby town of Etna. Her parents both worked at Dartmouth College—her father in theater and speech, her mother as a secretary. The couple met late in life, and Roach’s father was 65 when she was born. “Everyone thought he was my grandpa,” Roach says. Yet, she says, “My day-care center was the public library”; because he was retired, he’d take her along with him to the library every day.

Though Roach was an avid reader, she had no aspirations of becoming a writer. She got straight As all the way through high school and majored in psychology at Wesleyan University, only because, she says, “I wanted to go abroad for my entire junior year, and the psych department didn’t care.” Roach notes that she didn’t have a knack for science. “It wasn’t interesting to me, which is amazing to me now.”

Now Roach is one of the most popular science writers working. She regrets not taking those high school honors science classes “for the practical reason that my life would be easier if I had a better understanding of cell biology and basic chemistry.” But perhaps her beginner’s knowledge base helps to maintain her curiosity. “I visit researchers and end up using them as tutors,” she says. Roach compares herself to a sheepdog in her persistence in keeping scientists talking to her at a simple level, so that she can translate their work for a general audience. “One of my books was excerpted in a kids’ science magazine, and I asked them if they needed me to change the vocabulary to make it simpler, and they said, ‘No, you’re good,’ and it was at a sixth-grade level.”

After college, Roach moved west to San Francisco, about which she knew only its reputation for having really good dim sum. While she didn’t know if the move was permanent, she fell in love with California: “I didn’t have a career. I just decided to stay because it’s beautiful.”

Roach slowly built a career, starting out as a freelance copy editor, then working in public affairs for the San Francisco Zoological Society, writing press releases and dealing with reporters. But there was one problem: while dealing with reporters, Roach felt connected to them. “I’m not really a good spokesperson, because I tend to relate to the reporter,” she says. “Someone once called about a rumor of a cheetah dying from being sucked dry by fleas.” Instead of giving an answer, Roach responded to the caller with questions: “How many fleas would that be? How much blood does each flea draw? My boss said, ‘What are you doing? You’re supposed to do damage control.’ I’m too honest for that. I like communication to be straightforward. So I didn’t last very long at my public relations career.”

Roach’s next gig was freelance writing for various magazines: “I did a lot of fun reporting, which involved travel, which I love.” During this time, she wrote for the Hippocrates Health Institute magazine, Hippocrates, where she reported on medicine and health. She spent 15 years doing magazine features, because “back then there was a budget.” But that economic landscape eventually shifted, which helped prompt her to start writing her first book, in 2000.

Did Roach ever envision a career as a book author? “No,” she says. “I have a short attention span, and I tend to not do long narratives, which is usually what you think of as books. So I thought it wouldn’t work for me.” To this day, Roach attributes the start of her book career to her agent, Jay Mandel, who called her, suggesting she turn ideas from her Salon column into a book.

Writing that first book, Stiff, was an experience Roach calls “terrifying”: “A book is both incredibly liberating—you can go off on any tangent you want—but it’s also scary. There’s no manual about how to do it.” But Stiff took off, and Roach became a well-known pop science writer. Her accessible, morbid, and funny sensibilities writing about science have won her fans. Despite her lack of a scientific background, Roach says that as a freelancer she found herself drawn to science-centered stories. Looking back at her column for Salon, which she calls “very Mary Roach,” she says: “When given total freedom, I covered the fringes of the human body. It wasn’t a conscious effort. It was just me, left to my own devices, steered by my curiosity.”

Grunt came about when Roach was in India reporting for the Smithsonian magazine on the world’s hottest chili pepper. “The Indian military had weaponized it and made a natural form of tear gas,” she says. “So I went to the Indian Defense Ministry to talk about it and saw these other projects going on and realized military science is fascinating. You hear a lot about the military, but it’s always in the context of combat. There’s this whole world of science that doesn’t get covered. That’s what planted the seed.”

While Grunt takes on the science of war, and its accompanying effects, the book maintains its levity despite the seriousness of its topic. The book examines a range of dangers, from heat to bombs that cause flesh to “flower,”and introduces the scientists and engineers who work tirelessly to mitigate these threats. Alongside descriptions of blown-off limbs, there are passages on diarrhea and stink bombs. Humor is one of Roach’s calling cards. “The humor makes it more fun for me to write and even to report,” she says. “I’m definitely selecting places to go that will enable me to have some fun, not at the expense of anyone, but maybe myself. There are different ways to be funny. You can’t be funny about most things. I have the luxury of cherry-picking what I put in the book. So I’m looking for stuff that’s surprising, quirky, strange, funny, and hasn’t been covered.”

Roach’s books often deal with topics that evoke fear and repulsion. She puts herself in situations that many people wouldn’t be able to stomach. “I’m not afraid of anything in my books,” she says. “The body farm was definitely gross, but it was so interesting that it overrode any kind of revulsion. I’m not easily disgusted. It’s like my superpower.”

Roach also goes the extra mile to participate in research. For her book Bonk: The Curious Coupling of Science and Sex, she and her husband volunteered to do MRI coital imaging (which is exactly what it sounds like) for an experiment, except they didn’t get the privacy of being inside an MRI tube. “That would have been fine because it’s enclosed,” says Roach, who adds that the experience of having sex while wearing ultrasound equipment and being observed was “awkward, but fun to write up.” She goes on, “It was mostly my husband who had to deal with that. It was such a weird thing to ask him to do. He was an amazingly good sport about it. He has always agreed to help me with any of my books, but I took advantage of his generosity. It was memorable in a ‘what have I done?’ kind of way.”

Did writing Grunt change Roach’s perception of war? “I have a lot more respect for the people who not only serve as soldiers but the people who dedicate themselves to work that will make that experience more survivable or more bearable,” she says, adding that many working in military science “are not fans of war.” She notes: “If you spend a lot of your time dealing with the aftermath of war, it’s a pretty effective way to turn off war. It would be great if there was no war. But there is, and there probably always will be.”

Roach hopes that readers not only enjoy her books but come away with respect for the work of scientists. “It’s not an easy road to be a scientist,” she says. “They work really hard. And some of them do a lot of brave work. Most of the people in my books are working toward making people’s lives better, and they often labor unseen and unacknowledged.”