2312 is a very divisive book, and one that is perhaps a little bit too avant-garde for its the constraints of the genre. A kind of spiritual sequel to the Mars trilogy, 2312 is a solar-system hopping adventure of long-lived posthumans dealing with the politics of new technology. KSR's sublime joy at the wonders of the solar system is shines very very brightly: surfing the rings of Saturn, running with wolves across the Canadian tundra, looking up at the noon sun from the the surface of Mercury. Unfortunately, the things that most people look for in a book, like plot and characters, don't hold nearly as well.

A comparison with the Mars Trilogy is probably best. The Martians felt real, because the politics of terraforming were just like contemporary science politics, where values and intellectual achievement and personal feuds mix together in a toxic brew, but on a planetary scale. Everything flowed naturally from the attitudes of the First 100, and their conflicts with each other and with Earth. 2312 centers on diplomats and artists instead, and their attitudes and styles are not nearly as well-caught as the scientists of the Mars trilogy.

Let me try and describe: The protagonist, Swan, is a century old posthuman with an quantum AI in her brain (along with bird and cat neurons), Europan bacteria in her gut, and male and female genitalia. She's quit a career designing asteroid habitat ecosystems to follow the sunrise on Mercury. The death of her grandmother draws her into a conspiracy that does not trust the Quantum AIs vital to space travel and the Mondragon economy. She and Wahram (another posthuman with a slightly less extreme suit of augmentations) survive near-fatal experiences across the solar system, while tracing a unique space-based weapon in an age when total surveillance has rendered warfare obsolete, and trying to foment a healing revolution on sick and tired Earth.

Basically, the characters are spooks: diplomats, secret police, the elite self-appointed guardians of humanity. They are also calm, wise, quick to act, and never wrong. Historically speaking, these qualities are rarely (never?) found together. The very competence of the characters is both unrealistic and works against the idea that there are stakes in this novel. The deaths of thousands? Sure, but worse happens every week today. The end of human civilization. Unlikely.

And as mentioned, 2312 does weird, avant-garde stuff that IMO, does not pay off. The narrative is loose enough that it doesn't need random lists and incomplete passages from strange points of view.

Actually, thinking about it, this book would work much better without the grand plot. As a simple planetary travelogue, it's actually quite good, and human problems could help develop the posthuman protagonist.