Now that the first season of The Expanse is complete, it’s a good time to consider what’s different from the books, and whether those differences worked. Note: this post contains spoilers for Leviathan Wakes and Caliban’s War; if you discuss any of the later novels in the comments, please provide adequate warning.

Jules-Pierre Mao is directly responsible for the protomolecule experiments.

While Mao-Kwik was involved in the Phoebe, Thoth, and Eros incidents, Protogen was the chief architect of these plans (though it’s possible they were just a cover all along). Mao doesn’t appear to become personally involved until the Ganymede troubles in Caliban’s War. It looks like they may be merging the two evil mega-corporations for the show. This is probably a good idea, since making Julie’s father the big bad early on provides character development a faceless corporation couldn’t provide. This bit of streamlining would also make it easier for them to play with the timeline a bit in season 2, accelerating the Ganymede incident or possibly delaying the crash of Eros. Downside: Protogen is the perfect name for an evil mega-corp.


No vomit zombies.

While the protomolecule still turned its victims into a lethargic, infectious, vomiting mess, the show smartly avoid going with any zombie tropes. Instead, tension was maintained by the ticking clock of Holden and Miller’s imminent death by radiation sickness, along with the occasional clash with CPM/Protogen troops. Honestly, this was probably a budget-driven decision, but it worked well with the show’s measured pacing up to that point.


Avasarala suspects Errinwright ahead of schedule.

In the books, Avasarala only began to suspect her boss’s complicity in the protomolecule experiments about halfway through Caliban’s War (though to be fair, neither character appeared in Leviathan Wakes). It will be very interesting to see how her current suspicions affect her actions in the the upcoming season, particularly in regards to a certain Martian Force Recon Marine.

Show-only characters had a short shelf life.


When Avasarala’s spy Adam Jensen Kenzo joined the crew a few episodes ago, a number of book readers were expecting him to be a major, significant divergence from the source material, possibly even joining the crew. Miller’s detective pal Art Sami also looked like he might stick around for a while. Neither of them had a very good day on Eros.

Miller does not have his hat.

This is just unacceptable.