2312. It's an impressively detailed work that imagines human civilization expanding to nearly the entire solar system over the next 300 years (with Earth itself still suffering a lot of problems stemming from climate change and other factors). There's a city called Terminator on slowly-rotating Mercury (the city itself rides on huge rails in sync with the rotation to stay just at the edge of the transition between the dark side and the deadly sun-lit side of the planet, propelled by solar-heating expansion of the rails!). There are some 19,000 inhabited "terrariums" which are hollowed-out asteroids that rotate to create artificial G. Many different climates, biomes, and social systems are implemented in these asteroid worlds, some of which are in orbits that take them across huge distances in the solar system. So to transfer from Earth to a moon of Saturn, you would first ride a space elevator to orbit, and then take a shuttle that would transfer you to a suitable Saturn-bound asteroid world. Instead of spending weeks in a cramped spacecraft, you might spend those weeks in a 1G beach resort, or in an endangered animal preserve, or in an agricultural world growing food for export to Earth, or even in a low-G "flying world" where you might live something like a bird. Hundreds to thousands of people live in each of these small worlds.
There are a lot of powerful technologies assumed to exist, starting with fusion power, space elevators, self-reproducing assemblers, and quantum computers (personal versions are called qubes). But there is no magic here. While it's not inevitable that these technologies will become practical or widespread, they are physically possible. As usual (from having read Red Mars and Green Mars), KSR is at least as interested in social possibilities as he is in technical ones. And there are some weird ones in 2312. There's also a mystery and a love story or two buried in this book.
It's also interesting what a writer like Robinson can do with a very specialized piece of science - such as the braided or perhaps kinked F-ring system of Saturn (pictured above). Doesn't that look sort of wave-like? And where there are waves, surely you will have surfers, right? Some residents of the cities on Saturn's moons like to fly to one of the "shepherd moons" that give the F-ring its gravity-sculpted structure, and from there, they have figured out how to surf these narrow waves made of ice blocks! Yes, they wear spacesuits with thruster rockets, and they surf the F-ring. He even makes it sound sort of plausible. This is shown in one incidental scene between two of the main characters, Swan and Wahrom.
A funny thing about Swan: She is from Mercury, and she is an impulsive risk taker who has tried all sorts of bizarre things in her young 110 year life (most "spacers" live to around 200, with periodic DNA repair and other longevity treatments). She is really a wild character, an artist whose whole life seems to be a sort of over-the-top performance art. Just when I started reading about Swan, I happened to start listening to the new Fiona Apple album, and I watched her bizarre video for "Every Single Night." From this coincidence, Swan and Fiona have fused in my mind. So I picture Fiona when I read about Swan's latest odd adventure.
Although some reviewers are bothered by certain devices that KSR uses in this book, such as lists and excerpts of supposedly technical or historical documents (from the future), I think these brief inter-chapter devices allow KSR to fill in the back story and set the many scenes in a relatively compact way so he can cover the whole solar system and multiple characters and story lines without drowning the reader in too much detail (it's about 570 printed pages, though I am reading it on Kindle myself). Highly recommended if you like imaginative hard SF. There's a cool interview with Robinson from June 2012 here.