“One-eighth of all natural pregnancies begin as twins,” Leah Dieterich writes in her memoir, “but early in pregnancy, one twin becomes less viable and is compressed against the wall of the uterus or absorbed by the other twin.”

This concept of a vanishing twin, a term coined in the year of Dieterich’s birth, frames the author’s fascinating exploration of love, identity, sexuality and relationships. Though she finds her complement in her husband Eric, the twinship that is their marriage starts to diminish, or ‘vanish,’ just as her body had as a ballet dancer in her youth. Dieterich tries to figure out what drives her to fuse so strongly with certain people, what it is about her that fears being alone, and how individuality vanishes in a union. Maybe she lost her twin? Like the great essayists, her probing mind struggles to understand itself, and she makes fascinating connections between a range of subjects from pop culture to psychology to literature to help figure out who she is and what she wants.

Vanishing Twins is a powerful, poetic memoir, both emotive and cerebral, that casts new light on the familiar issue of relationships, marriage and storytelling, and vividly articulates some of the most subtle aspects of human relationships in a way many readers will recognize in themselves.

When did you start writing about your relationship with your husband and your own identity?

I started writing Vanishing Twins about six years ago, but before that I’d explored some of the same themes of love, language, and identity in fiction. I’d also started a screenplay for a film about a couple trying to define their individual identities while maintaining their bond, who meet a set of identical twins who are trying to do the same. Sexual entanglements ensue. I was really only at the research phase for this film, interviewing a set of twins that my husband was friends with, and I got so into our correspondence and the other research I was doing about twins (and relationships and sexuality) that I realized I needed to pursue this topic in a more essayistic way.

When I tell people about your book, I emphasize not only the subject matter but the way you approached your story. To me, you turn the memoir on its head by staging the text in a poetic way on the page, and by alternating essayistic diversions with the larger narrative to explore related themes. How did you find your book’s inventive form?

I have writers like Maggie Nelson and Sarah Manguso and many others to thank for the form. I really love the numbered aphorisms in Bluets but knew that felt too academic for my project, though I have always loved the way Nelson can synthesize the ideas of great thinkers into her own personal narrative. I assume it means she’s a great teacher, though I’ve never studied with her. I was a private student of Sarah Manguso’s and learned a lot from her about concision and how it is possible to make something very weighty out of only a few words or paragraphs. I like the term “staging” that you use, as well, because I feel that my writing has been informed by my background as a ballet dancer. In dance, you are constantly arranging and rearranging your body in space. This is how I treated the various sections of the book. I moved them around until they seemed fluid like a dance.

You work in advertising, but did you ever formally study writing?

I haven’t formally studied writing in a degree program. I cobbled my writerly education together from a couple of UCLA extension classes, a week-long workshop in Mexico, and two long-term private student relationships, one with Chris Daley who leads Writing Workshops of Los Angeles with whom I met with weekly for two years while generating the first draft of Vanishing Twins, and the other with Sarah Manguso, who gave me notes on two drafts of the book over the course of the following two years.

How has your ad career informed your literary ventures?

Advertising writing requires a lot of concision, so it has very much informed my inclination toward brevity in my literary work. Being a copywriter and having my headlines or TV scripts rejected (and sometimes accepted, even lauded) by my boss on a daily basis prepared me well for the rejection I’d have to face on the way to publishing a book.

People often describe writing about our lives as “cathartic,” but that isn’t the point of a lot of personal writing. In your book, you’re searching for answers, for a deeper understanding. Do you feel that you’ve achieved a new perspective on your life now?

I definitely gained perspective on the period of my life that I’ve explored in Vanishing Twins. I always write to understand something, whether it’s something about myself or something about the world at large. It’s the way I process my thoughts. When I’m writing or revising with the intent to publish, I’m always doing so with David Foster Wallace’s intention—that the purpose of literature is to connect, challenge, and ultimately make us feel less alone. So while it’s true that writing about one’s life isn’t necessarily “cathartic,” there is a visceral element (connection with other humans) for both reader and writer when it is done successfully.

Sometimes the people who become characters in our stories feel betrayed or mischaracterized, or feel they get should an editorial say in the text. Has writing about the people in your life caused any tensions?

Of course. But these tensions were an important part of the project itself. I had to find a way to honor my autonomy and my individual voice as an artist, while simultaneously respecting the differing opinions, memories, and thoughts of someone I love deeply. In a lot of ways it’s a continuation of the journey begun by the self who narrates the book. Luckily my husband is an artist himself, and a lover of literature and philosophy, which made the process easier. Many of the events in this book happened more than a decade ago. To have the opportunity, though painful, to revisit them has helped us realize how far we have both come together and individually since that time.