There will be spoilers ahead—you have been warned!

The current king of the space opera genre is James SA Corey. Corey—a pseudonym for Daniel Abraham and Ty Franck—first appeared in 2011 with the critically acclaimed novel Leviathan Wakes, the first installment in an increasingly epic series called The Expanse, about war and solar system colonization. The books have recently been translated into a TV show on Syfy, and my colleague Annalee Newitz is spot on when she says it’s the best thing in years. But having just reread the books, seeing the story come to life on the screen has given me a little “canon shock.” Even so, working through this reaction has helped me think more about how the writers on the TV series have tweaked the story to work better in a visual medium.

TV and movie adaptations run a certain risk with fans of a well-loved book—few Dune aficionados have much love for the Lynch movie or the SyFy show, for example. Actors get cast for roles you always imagined as someone else. Plot changes can feel disconcerting, like a newly chipped tooth. Does an author’s involvement in the process help defend against canon shock? I’d argue it can—the various radio, book, and TV versions of The Hitchhiker’s Guide to the Galaxy fall on this side, for instance.