This is book 3 in the Expanse series and it continues to follow James Holden and his crew as they travel around the solar system. There isn’t a lot I feel I can say about this book that you won’t find reading a review on Amazon, and I don’t want to give any spoilers. This series continues to be good quality hard SF and I really have enjoyed reading it. The authors are careful to use realistic physics in their ships and their acceleration which is one of my favorite aspects of the books. It is definitely hard SF, but with sufficiently advanced technology as to be indistinguishable from magic*.
An interesting twist in this story is the continued presence of the generation arc that was repurposed as a military vessel in book 2. The ship was designed to accelerate at one end of the journey, spin along its axis to simulate gravity for 99% of the journey, and then decelerate at the end. However, since the ship has been repurposed, it is always under thrust and that changes how they use the interior spaces. It’s fairly minor details like this that make the story seem so much more believable.
I continue to be amazed at the depth of the world and how the different characters have such different personalities. The book is written in a close third person, following about 5 characters around. This book finally gets to the heart of what the protomolecule is or was, and I am really looking forward to seeing what happens in future books. It seems like the story is still getting started. The book is epic. It is hard for me to imagine keeping all of this world straight, and I guess having two authors collaborating makes it somewhat easier. Very good SF.
*note: one of my collaborators once improved this quote and I like his version better. Sufficiently advanced technology would be indistinguishable from a toilet. It’s there, you don’t think about it, it always works.