Karen Joy Fowler begins her sixth novel, We Are All Completely Beside Ourselves, by inviting – OK, requiring – that the reader delve into the middle of the story. “Skip the beginning. Start in the middle,” says the book’s narrator, Rosemary Cooke, in the prologue. “The middle of my story comes in the winter of 1996,” Rosemary, then college-aged, explains at the start of Chapter One.

Fowler’s narrative structure may depart from the norm but so does the Cooke family. Rosemary’s sister, Fern, disappears when she’s five years old. In response, Rosemary shuts herself inside herself and all but stops talking. Her older brother (and only other sibling) Lowell starts acting out. Halfway through his senior year of high school, Lowell runs away from home, and, within a week, becomes an animal activist and a fugitive.

For the next two decades Rosemary and her parents rarely mention their missing family members. There are occasional, cryptic postcards from Lowell, but nothing from Fern. So Rosemary actively then involuntarily suppresses Fern’s existence. Childhood memories with Fern remain absent until Rosemary returns home, where recollections are unearthed. With each new detail, the reader becomes increasingly invested in finding little girl lost, or at least finding out what happened to her.

Then the big reveal: Fern is a chimpanzee.

To accurately portray Fern’s role in the Cookes’ lives, Fowler began the story in the middle of Rosemary’s, when her memories of Fern return along with a profound sense of loss. “I still stand by that decision. I wanted to talk about Fern as a sister for a while before talking about her as a chimpanzee,” says Fowler. “I wanted you to [first] think about Fern as a human being with a stress on the being.”

Of course, with books, like movies, you can only bury the lead for so long–until the first review comes out, if not before. “I did not really think long and hard about the marketing conundrum that I was creating for my publishing house,” Fowler confesses. (There was debate as to whether or not to put a chimpanzee on the book cover.)

Knowing that Fern is a primate before meeting her does not, in any way, lessen the experience that is reading the book, which is complex, emotional, and a literary accomplishment. The story itself is astounding.

Fern entered the Cookes’ lives at almost exactly the same time as Rosemary. They were born months apart and, until Fern disappeared, were raised together. The coupling was meant to be an experiment. (Rosemary’s father was a psychologist who studied animal behavior.) The experiment backfired.

There’s a history of scientists conducting similar research projects, where parents attempted to rear a child and chimp at the same time in order to study developmental differences. Fowler weaves these very real stories into the fictional one, beginning with that of the Kellogg family, who, for nine months in 1930, raised their infant son alongside a baby chimp. The study was shut down after the boy started sounding like a primate.

It was the Kellogg story that precipitated We Are All Completely Beside Ourselves. Or, rather, Fowler’s retelling of it to her daughter. “She said, ‘What would it be like to be that kid? You should write that story,’” recalls Fowler. “And the minute she said it I thought it was a great idea.” Fowler’s father, an animal behaviorist, was also an inspiration. His experiments mostly involved rats navigating mazes, but he and his daughter often argued over whether or not animals could think. “In his mind, thinking was a human trait,” says Fowler. “Although, in his defense, he didn’t think any of us were all that intelligent.”

To write plausibly about chimps, Fowler needed to do extensive research, including attending a “Chimposeum.” (Who knew such a thing existed?) In the process she became increasingly interested in animal cognition. “The biggest surprise to me in the research was how many kinds of intelligence there are in the animal kingdom and how little we’ve paid attention to it, or even tried to understand it until relatively recently.”

In part, Fowler’s book is about the dividing line between animals and humans. “It seems to me we’re much more embedded in the animal world than we have acknowledged to ourselves,” Fowler says.

Rosemary’s father drives home the point when he notes, “the only way to make sense of the U.S. Congress is to look at it as a 200-year primate study.”

“There’s lots of dominance displayed, lots of chest beating,” Fowler adds, when asked about the line. Throughout the story she makes it clear that primates often seem far less savage than the people studying them. The information and imagery are, at times, not for the faint of heart; however, Fowler does a fine job of balancing out the emotional and visual heft with humor. 

We Are All Completely Beside Ourselves is multi-layered. It’s about the unreliability of memory and it’s about language, which is at the heart of what Fowler calls the “debate about what it means to be human and what it means to be a human animal.” 

Prior to Fern’s leaving, Rosemary talks incessantly. She uses abstruse words to outshine her other half, who uses sign language. Everyone imposes meaning to Fern’s gestures, but how capable chimpanzees are of communicating with humans remains up for debate, as does the role language should play in determining animal intelligence. Also undetermined: chimpanzees’ place on the animal-human spectrum. Fowler is quick to admit to a fluctuating point of view on all fronts.

“In general it’s not interesting to write about things you actually know and understand and have well-reasoned opinions on,” she says. “It’s much more interesting to write about the things on which you’re quite confused and still groping your way around and may in two months or five years or 20 years decide that you were completely wrong.”

Tobin Levy is a writer living in Austin, Texas.