This is a near-five-star read. Really excellent writing, storytelling, and intelligent critiquing/interrogating of culture. Shusterman has an absolute genius for weaving exciting, twisty plot threads and more character arcs than should be possible together at the last moment for explosive, satisfying endings. Loved so many characters, but especially (mildly spoilerish warning:) Gracie, the "low-cortical" surprise hero who uses her particular skills to basically save the world. I think she's supposed to be something like autistic? But her way of looking at the world turns out to be exactly what's needed. Awesomeness.
This is still a pretty depressing premise that calls out human selfishness and irresponsibility in a big way, to the extent that the ending was somewhat implausible, but who wants to read a series about how we're ruining the world with no happy ending in sight? I enjoyed the read, and loved (/feared) the chapter-intro content all the way through the series. In early books, Shusterman used PSA and marketing-style ads to play up the way propaganda and corporate manipulation/marketing worked on people's fears and clouded their thinking. This last book uses actual headlines and articles from the last decade or so to show just how terrifyingly plausible this dystopian future really could be. Smart way to build tension and horror undertones (overtones?) while also proving that the author did an incredible job on the research and world-building.