With Star Wars: Rogue One just around the corner, fans are beginning to wonder how the Galaxy Far, Far Away translates from the era of The Revenge of the Sith to that of A New Hope. Rogue One takes place just before the events of that first film, and will introduce viewers to an entirely new cast of characters. To help set the stage for the film, Lucasfilm turned to veteran Star Wars author James Luceno to write Catalyst, the first novel that will tie in to the events of Rogue One.

Catalyst takes place shortly after the events of Revenge of the Sith. The Empire has begun work on a massive project known as the Death Star in order to assert its control over the galaxy; one of the leaders of the project, Orson Krennic, recruits an old friend, Galen Erso, to help with its completion. While Erso believes that his work will be used to help people, Krennic has other ideas, and the scientist unwittingly finds himself a pawn in a much larger conflict.

We recently spoke with Luceno by email about his work on the book, and where it falls in the Star Wars universe.

Your next novel Catalyst is a tie-in to the upcoming Rogue One film. You’ve written several novels that tie directly in with upcoming films (such as Cloak of Deception and Labyrinth of Evil): how was writing Catalyst different from these books? How was it the same?

Star Wars films start with the proverbial bang. An exotic setting is established, a few lines of dialogue are exchanged, and the action begins. Assaulted by blaster fire and strobing explosions, we’re not inclined to wonder about the backstory, whatever concatenation of events brought us to this particular deadly moment. Besides, we know that before too long we’ll get just enough exposition to satisfy our curiosity about what came before. The formula isn’t tampered within Rogue One. But for those in search of added detail, the full story, there’s Catalyst.

As was true with previous tie-ins, I began by asking myself when and where the full story began, and I went in search of the younger versions of the characters we’re introduced to in the film. The difference this go round was that I didn’t have a specific line of dialogue to serve as a jumping off point — the “baseless accusations” that imperiled Chancellor Valorum in The Phantom Menace, which provided the plot for Cloak of Deception, or “that business on Cato Neimoidia,” which was the springboard for exploring Obi-Wan and Anakin’s friendship in Labyrinth of Evil. What Rogue One makes clear, though, is that two of the major characters had a prior relationship, and that relationship was what I had to unearth.

What is Catalyst about? How does it set up Rogue One?

Initially I wanted Catalyst to cover a lot of bases and feature a multitude of characters, including the Emperor and Count Dooku. But as the novel developed it became clear that I needed to focus on a select few, and spread their backstories over a course of years rather than days or weeks. And so the story focuses on Imperial weapons specialist, Orson Krennic, and preeminent scientist, Galen Erso, along with his wife, Lyra, and their young daughter, Jyn. Krennic serves the Republic, then the Empire unflinchingly, where Galen wants nothing to do with war or politics. Only his family and his research matter. Fatefully, Galen’s passion for the latter places him and his family in peril. In detailing the relationship between Krennic and Erso, I had to determine when and how they met, and the nature and depth of their relationship. I knew that I had to create a story that informed the movie rather than spoiled or mimicked it. I had to determine how much foreshadowing I could do without being too much on the nose. Basically I needed to set the stage for what unfolds in Rogue One, even though decades elapse between the novel and the film.

You’ve written about Death Star-related characters in the past with your novel Tarkin. Did that book help inform any of the events or characters surrounding Catalyst?

Catalyst is as much a prequel to Tarkin as it is Rogue One. Governor Tarkin plays an important role in the novel, and I credit the earlier novel with spurring me to think long and hard about the early days of the Empire, which I touched on briefly in Dark Lord. The transition years between the end of the Republic and the beginning of the Empire are fertile ground. Several authors have made reference to events that took place during that time, but few have delved deeply. With the Senate relegated to a back seat, the Emperor’s court rises to prominence, with people like Krennic and Tarkin jockeying for position, currying favor, and exploiting every possibility to ingratiate themselves with the Emperor. Even the Emperor was testing the waters, gauging just how much he and his advisors and courtiers could get away with, especially with regard to the ultra-secret Death Star Project, which is central to the events depicted in Catalyst.

Did you have to work around any other novels or works, such as Star Wars Rebels?

While referenced in a few Legends novels, the early years of the Empire remain largely unexplored territory. Since Lords of the Sith, A New Dawn, and Rebels are set years after Catalyst, the only novel I really had to adhere to was Tarkin, which first got me thinking about the Death Star’s planning and initial construction phases, as well as the shift in goals for career militarists like Tarkin and Orson Krennic, and career politicians like Mas Amedda, Ars Dangor, and others. Fortunately, many characters long associated with the development of the Death Star didn’t need to be overwritten, as the decades of assembly leave room for one and all.

Something I found interesting in the description is the mention of separatist kidnappers. Are these the same separatists as in the Prequel trilogy? How does that movement inform the Rebellion?

Catalyst begins a few months after the start of the Clone Wars, and the Separatists referred to in the description are in fact aligned with the Confederacy of Independent Systems. A direct link can be made between the Rebellion and the former Separatists, who, in the wake of the Republic victory, never received reparations promised by the Empire, and remained ostracized — and in many cases occupied — while the Empire spread its tentacles far and wide. Instead of fairness, the galaxy fell victim to fear of the Empire’s ever-expanding military. The absence of the Jedi Order — their fire gone out of the universe — left many worlds without any recourses to counter injustices. More important, and in the same way the atomic bomb emerged from World War II, the Death Star was birthed durning the Clone Wars.

Star Wars: Catalyst is in bookstores today.