I received this book free to read from Goodreads.
Overall, an engaging read. Falls off a bit at the end.
This book has a viewpoint character as someone who was manufactured, and is completely non-terrestrial. He has to navigate a terrible choice between extinction of two planetary species (Jovian and Terran) from an implacable foe. And he has to do this by being an artful negotiator. He occasionally receives insane-looking directives from his AI counsel (Wisdom), which is supposed to help him thread this needle. Most of them pan out, with one glaring exception. In the process of these negotiations, he manages to disarm the nuclear stockpile of all countries of Earth (no mention of rogue nukes).
I love the plot of this book, as the protagonist is tuck between a rock and a heard place for almost the entirety of the book. Some of the technical aspects of it I found annoying, like how his super spacecraft that can transit from Jupiter to Earth in four days isn't bulletproof, or no mention of how loud a bullet hole whistling out the entire atmosphere of a space craft would be whistling. Ultimately, you have to forgive those sorts of things.
The one thing that really bothers me is why the AI tells him he needs all the sand on Earth, and that they're willing to give it up. This is never answered. While the sand is considered extremely rare and valuable outside of Earth, why couldn't he just make off with a few thousand tons to pay for his retirement? Sand has value to regular people, while nukes do not, so it feels like the governments of Earth would balk at giving it *all* to him. Also, he has no way to carry it off. Even stranger was that the Jovians were willing to give up their magical Jupiter sand, because they need it to live. They would all die without it.
So, great up until the end. I suspect writer's fatigue.