So, the book series is absolutely finished. The ninth novel, 'Leviathan Falls', came out in late 2021 and it's the definitive end. James S.A. Corey (the pen name for Daniel Abraham and Ty Franck) wrapped up the main arc in a way that felt both immense and surprisingly personal. There's a finality to it that I appreciated, even if it left me staring at the wall for a good twenty minutes after I finished.
Now, there are still the novellas—they’ve collected most of them in 'Memory’s Legion'—which add fantastic color to the universe. But the core saga of the Rocinante, Holden, Naomi, Amos, and Alex? That story is complete. It’s kind of a relief, honestly, to have a monumental series actually reach a planned conclusion instead of stretching on indefinitely. You can start the journey now knowing there’s a genuine destination.