Stef Penney’s second novel, The Invisible Ones, sets the mystery of a missing girl in the always mysterious world of “the Travellers,” the English Romany gypsies.

What made you decide to write about gypsies in the 1980s?

It takes place in the ’80s because I wanted to set it before the Internet changed the investigator’s job so thoroughly, when people couldn’t communicate too easily. I’d had a lifelong fascination with Romany Gypsy culture, possibly because it exists on the margins of wider society, and not that much is known about it. I think for most people, anything secretive and mysterious is fascinating—and that seemed to chime with the idea of a noirish story. In a noir the protagonist, classically, goes into a closed, secretive world and has to negotiate the hidden shoals. That whole world seemed very under-represented in news, culture, fiction... I just hope that the more portrayals of Traveling peoples exist in culture, the more balanced the overall picture becomes.

Was it difficult to write about such a closed society?

The short answer is yes, it was! Initial field research proved unhelpful, or rather, proved that I’m really bad at interviewing people, so most of the useful stuff I learned was from books, documentaries, the Internet.

Your first book was about a missing person, and you have a missing young woman driving the plot in this one.

I’ve had to think about this quite a lot. I don’t deliberately sit down to write about missing people, but the missing are fascinating because there are so many possible reasons for a disappearance. The story behind it could be a thriller, a tragedy, or a picaresque. Maybe there’s an element of envy there, as well as curiosity and dread—what if we really could do that, abandon a life that’s too messy and compromised, and start again from scratch? When I was young and impressionable I read Picnic at Hanging Rock by Joan Lindsay. I was seduced by the languid sensuality of its setting and knocked out by the boldness of her decision to give no answers; perverse, brilliant, unforgettable. It haunts me still.

What was the inspiration for your middle-aged PI, Ray?

I think I have to go back to my love of classic Hollywood noir. The world-weary, emotionally battered private eye is a massive cliché—and it’s one that I adore—but I have tried to twist it into something a little new. Usually they are hard-boiled and tight-lipped; Ray is neither, nor is he especially competent. He bumbles through the mystery in a way that any of us might. I also wanted to explore just how devastating the aftermath of a marriage breakup can be.

Why did you choose JJ, a teenager, and Ray to tell the story?

Ray came first, the outsider discovering the story (although not entirely an outsider, being half Romany), so he gives some context to this secretive world. And JJ, who is Romany, provides the balance, being inside the family... and I just love writing teenage boys (make of that what you will).