In her newest book Grunt, science writer Mary Roach explores the nooks and crannies of a huge enterprise: the United States military. With her trademark wit and zeal to learn every intriguing fact, Roach takes readers through the multitude that is the armed forces, from military fashion to submarines. We spoke with Roach about her approach to writing about this unknown world and discussed her peek beyond the civilian-military divide.

At many points throughout the book, assumptions about how something is used or what it might mean turn out to be pretty far off the mark. How did you approach that learning curve?
I was doing my normal geeky science writer thing. The book brought me into contact with people who’ve been severely damaged by their experience in combat. It was not so much a learning curve, but just a [feeling that] this is intense and beyond any kind of reporting experience I’ve ever had and that I don’t even know what to say or ask. I showed up with questions about surgery and procedures and I’ve got my notebook and I’m [asking] “How do you rebuild a urethra for somebody who’s sustained injury?” And then to actually sit down with somebody who’s lived through that, who’s stepped on an IED and hear somebody say to me, “I was blown through the air and I hit the ground and I saw that my leg was gone and I put on my tourniquet.” Just the straightforward presentation of that fact was kind of overwhelming. I was just sort of scrambling to process that and make sense of my role as a science writer because it’s such an intimate and powerful thing that these men and women have been through. I think of all the books I’ve done, it felt weightier in a way, and I felt more of a responsibility as a writer.

What did your research and writing experience teach you about the civilian-military divide?
I was very conscious of being an outsider to the experience of combat and deployment, but I didn’t really think of “the divide.” I hadn’t really heard anyone refer to the civilian-military divide. But now, it’s so clear–they’re different cultures, the military is a culture unto itself. This was almost like visiting another country in a way, just learning how people think and how they speak and what their experience is. Service is such an intense experience and a transforming experience; once you go through it, you probably see civilians somewhat differently. But nobody ever made me feel like an outsider, people were unbelievably generous with their time and welcoming.

Having heard a lot about tinnitus from friends and colleagues, I found the earplugs chapter very interesting! What was your favorite subject to dig into?
Oh that one was super interesting to me. [Tinnitus is] the kind of thing that because it doesn’t hurt and it’s cumulative, you don’t really think about it. This was a really interesting chapter for me just because you don’t see hearing loss, you see a prosthetic limb, you see certain injuries and that’s what you tend to associate with war. But hearing loss is huge and it’s just such a sticky problem…I’m always looking for the [subjects] that fall through the cracks, like hearing loss or heat injury and heat illness, that seem trivial and silly but are really not.