It began as a role-playing game. Twenty years and over one million words later, it is a bestselling series of nine books that have reimagined the idea of a space opera and spawned an acclaimed television series. It is The Expanse, a triumph of creative imagination that presents a plausible future for humanity as it ventures beyond Earth to establish communities throughout the solar system.

The novels, which are rich in drama and action, and which have been compared to A Song of Ice and Fire, balance nuanced characterizations, economics, politics, and issues such as medical ethics, race relations, and equity. This November, the 2020 Hugo Award winner for best series, written by Daniel Abraham and Ty Franck under the pseudonym James S.A. Corey, ends with Leviathan Falls, a satisfying conclusion that doesn’t pull its punches.

The creators, who were interviewed over Zoom, had not expected to write an ongoing series. Abraham said that he was surprised that he and Franck completed the whole thing, especially after they’d added the equivalent of second full-time jobs as executive producers of the TV adaptation that began airing on the Syfy channel in 2015—prior to their writing the sixth book.

“It’s ridiculously ambitious, doing this many books, with this huge scope, starting off with kind of late Apollo 13, and doing the whole arc up into showing how the Galactic Empire happens,” Abraham said. “That’s really easy to conceptualize over beer one afternoon, and it’s really insane as a thing to take on for a decade, and then be able to pull it off.”

Franck recalled, “When Daniel said, ‘Hey, you’ve got all this cool stuff—do you want to write a book with me?’ My answer was, ‘Yeah, sure. I’ll try that. That sounds fun.’ But if Daniel had said, ‘Hey, you’ve got all this cool stuff—let’s do a nine-book, million-and-a-half-word epic, along with a collection of short stories,’ I probably would have said, ‘No.’ ”

Their aspirations were extremely modest initially. “The original concept for this was we would write Leviathan Wakes and sell it for pizza money,” Abraham said.

Franck added, “We didn’t have high expectations for it being a big new title or anything. And that’s what Daniel means by pizza money—you know, you could sell it for a few thousand bucks, and high-five each other, and that’d be the end of it.”

They did have a firm idea of where their story could continue after that first novel, however. “When we sent it out, we wrote one-paragraph outlines of what the next two books would be,” Franck said. “We sent that to the publisher too. And they bought three books based on one complete book and two one-paragraph blurbs. It was when we started writing the second book that we actually sat down and said, ‘Let’s have a good plan for this. Let’s figure this out.’ And that was when we really started to plan out what the longer story would be.”

The plan, inevitably, changed a bit. While the authors once contemplated writing 12 books, they cut out three after realizing their ideas for what would have followed the sixth book, 2016’s Babylon’s Ashes, were just a “boring rehash.” Instead, the seventh book, 2017’s Persepolis Rising, featured a dramatic time jump that allowed the authors to give the solar system time to stabilize after the events of the prior book.

Not much else changed, though. Franck said he had pitched “the last scene and the last line of the last scene” of Levithan Falls to his colleague around 2012.

The Expanse has sold a total of four million copies in North American and has been translated into 21 languages, according to Orbit, its publisher. Interest in the series has continually grown and Levithan Falls has a first printing of 125,000 copies.

Abraham is quick to credit his collaborator for the series’ remarkable success. “The thing that made me excited about doing this in the first place,” he said, “was the depth of worldbuilding, and the imagination and the effort that Ty had put into it before I came onboard at all”—when The Expanse was just a game Franck had created.

Franck reciprocated the praise when he shared the challenge of finishing Leviathan Falls. “There was a stretch where what we desperately needed was about a month sitting in the same room,” he said. “And because of Covid, we couldn’t make that happen. And that really put a strain on getting that done. We just needed that time to sit and talk through it, and get it all nailed down. Daniel was an effing hero there at the end.”

Fans of The Expanse can look forward to one more glimpse into the intricate universe Abraham and Franck have constructed. In March, Orbit is releasing Memory’s Legion: The Complete Expanse Story Collection, which features a never-before-published novella. But that will be it. Abraham commented that “part of the craft of making something like this is not doing everything.”

The authors will be moving on to another imagined future; they have signed a deal with Orbit for a trilogy set in a completely different universe. Abraham only shared that “it’s ambitious in a different way, and a very different part of the space opera spectrum, with a very different voice than The Expanse had. It’ll stretch us some.”

Lenny Picker is a freelance writer and PW reviewer.