It all started on a weekend away for the Booksluts, a Sydney book club with the motto “We’ll read anything.” Six of the group’s eight regular members were discussing “Crime and Punishment,” and talking about the club’s upcoming tenth anniversary, which they dreamed of celebrating with a Trans-Siberian Railway trip. They jokingly decided that they would fund the trip by writing a novel together. Much vodka had been consumed by this point, and plot discussions degenerated into mass hysterics.

But the next morning the friends went out and bought butcher paper and Sharpies and spent all day brainstorming. They decided that their novel would be a rural romance, set in the Australian outback, and agreed on the backstory of their heroine, a city girl who inherits the farm where her father—now mysteriously disappeared—grew up. Sparks would fly when she meets the handsome (and engaged) cattle farmer next door.

The Booksluts returned home with assigned scenes to write and unspoken doubts that the project would go any further. Everyone was surprised when the completed scenes began arriving, like clockwork, in their in-boxes. A few months, meetings, and reshuffles later, there was a core group of five women—Jenny Crocker, Madeline Oliver, Jane Richards, Jane St Vincent Welch, Denise Tart—a few of whom had writing experience (mostly in journalism or comedy), and some of whom had no writing experience at all. What they did have was practice, thanks to about a decade in the same book club, at picking apart novels and voicing their opinions to the group with confidence and respect.

For the next three years, they met as often as they could—usually at least once a week—and wrote in every spare moment they had, between full-time jobs and family duties. They figured out a system to manage the logistics and decision-making quandaries of group writing along the way. They took a road trip to the farming region in which their novel was set, far west of Sydney, and realized that they’d got a lot wrong: the soil was black, not red; the white stuff on the bushes wasn’t trash but cotton that had fallen off trucks.

The erotic passages were a struggle to write at first. They each submitted anonymous versions of the book’s first sex scene, an approach they later described as “you show me yours and I’ll show you mine,” but they quickly figured out who had written what—they knew one another too well—and they very vocally disagreed about what was legitimately steamy. (The scene that made it into the book blended all their versions.) With time, they lost their inhibitions about writing, or talking, about sex, but they remained cautious about how they labelled these scenes as e-mail attachments, in case their teen-age children got nosy. (“Washing Machine Instructions” was a good one, “because we knew no fifteen-year-old would open the document.”) They’re proud of the risks they ended up taking: their heroine masturbates early in the novel, often a no-no in traditional romance, and they included a controversial scene in which she has sex with her love interest in a cave above her father’s skeleton.

Friends and family were fascinated by the project but sometimes seemed to be betting on how long it would take for the group to fall apart. Yet, through house moves, job changes, and illnesses, the women kept writing, because it was fun—exhilarating, really—to create something together.

In late 2013, they sent their manuscript, “The Painted Sky,” to a major Australian publisher. It was the only place they submitted it, and they were stunned by the response: I read your book, could not put it down. The publisher was impressed with the novel’s unified voice and evocative descriptions. Next thing, they were picking out a pen name for their soon-to-be-published novel. They settled on Alice Campion—their publisher had recommended a surname starting with a letter that would be stacked at eye level in bookstores, and a first name with an Australian flavor (cf. Alice Springs).

To celebrate, the Alices, as they now call themselves, got matching bracelets made from antique typewriter keys, and immediately began working on a sequel.

Around the same time, in Cape Town, South Africa, three women—Sarah Lotz, Helen Moffett, Paige Nick—decided over a champagne-fuelled lunch to write a series of choose-your-own-adventure erotic novels. The “Fifty Shades” books were then in their heyday, and the women were annoyed that, after decades of feminism, the heroine of those books was the stereotypical “innocent virgin” being “broken in” by a man. They thought it would be fun to invent an experienced heroine who puts her sexual partners through their paces. They all already had busy writing-related jobs centered around creative collaborations with others—in advertising, as a horror/speculative writer (who sometimes wrote with a partner), and as a “recovering” academic/editor. They were all workaholics.

On the way home from lunch, one of the writers started composing a scene in her head; she didn’t stop writing until late that night. Then she e-mailed what she’d written to the others. Another member of the group, an insomniac, took up the baton. The third called her agent and pitched the premise to him. “This is either mad or brilliant,” he said. On the basis of the pitch, their first book, “A Girl Walks Into a Bar: Your Fantasy, Your Rules,” sold in twenty-one countries. They had just over a year to write three books in the series. For their pseudonym, they chose the compound Helena S. Paige. (“Helena sounded more porny than Helen, and Sarah only agreed to us including her initial,” they explained.)

Though novels written by three or more people are rare, the Helenas knew that co-writing duos are not uncommon, and that other forms of artful entertainment (TV shows, movies, plays, songs) are usually the product of collaboration. They didn’t think novels should have to be any different—especially in a genre like erotica, where readers aren’t necessarily seeking a distinctive view of the world but are looking for an engaging, arousing read with an unexpected plot twist or two.

They started relay writing, and soon hit some obstacles. One of the writers found that she froze every time the heroine was about to have sex. (“Sex scene goes here,” she’d write, after doing the buildup.) Another was suffering from temporary partial retrograde amnesia after being hit on the head during a home invasion. (“When I regained parts of my memory, four months later,” she likes to joke, “I discovered with amazement that I’d co-authored an erotic novel!”) They often resorted to choreographing the sex scenes to see which bits should go where; on one occasion, they realized that their heroine would need three arms to manage all that they had her doing in a particular encounter. They banned “lady garden” from their vocabulary of euphemisms, bought a pink cock ring to see how it worked, and formed a pact that, if any of them died during the writing process, “one of the others would immediately decamp to their computer and delete their browser history.”

Happily, they discovered that they had complementary skills: plot mistress, workhorse, ruthless editor. It was gruelling, and insanely fun. It was a project that none of them would ever have dreamed of doing alone. They started calling one another the Elves: as in the Brothers Grimm story “The Elves and the Shoemaker,” writing a novel as a group, when it’s going well, can feel almost magical, as the book seems mysteriously to grow and grow overnight, quite apart from any individual effort.