'll admit that watching the Expanse television show spoiled this book for me. I already knew what was going to happen, so there weren't too many surprises in this book because the show kept close to the source material. Even with this a priori knowledge going in, I found Abaddon's Gate to be my favorite book of the series so far. The plot felt like it was actually getting somewhere instead of just dancing on the edges of the important series arc that finally solidified in this book.
Some of my favorite moments of the series were retained in the written form of this book, including the description of the first "sudden stop" when someone tried entering the alien portal. The human drama was also interesting because it wasn't entirely geopolitical but wove in elements of religious beliefs as well. It helped that the crew members of the Rocinante are fully fleshed out characters by this point in the series, since these books really are about how they react to being in the middle of this interplanetary (and now intergalactic) alien conspiracy. And while it might be nice to have the "character of the day" stick around for more than one book, I understand the decision to only focus on the Rocinante throughout the series.
As with previous books in the Expanse series, Abaddon's Gate excels in its depiction of realistic science in a fictional setting. Unlike more traditional hard sci-fi, this book uses these moments of real science sparingly to drive the plot forward instead of stopping at every instance and lecturing the reader as to the mathematical physics behind what is happening. This is so effortless in its execution that it never distracts from the action, which keeps the pacing at a nice, brisk action-based pace.
An exciting turning point in the Expanse series, I give Abaddon's Gate 4.0 stars out of 5.