In pocket summary, it picks up as the second - and successful - Martian revolution is concluding, on a Mars newly liberated from a flash-flooded Earth. Thanks to anti-aging medical technology, much of the original cast of Red Mars is still with us, together with their first and second generation children. These assorted narrators take us through factional Red (pristine, lifeless) and Green (transformed, bountiful) fights, fumbling efforts to kick-start Martian politics, and the solar system-wide issue of humanity's abundance in the wake of this anti-aging.
However, that description can't touch just how ridiculously broad the canvas here is. As well as the geology of Mars and the science of its transformation (both global *and* local), the socio-economics of its political awakening, and the gathering pace of solar system expansion, the novel finds time to take in (among other things) life in southeast England on a drowned Earth, sex-and-hunting cults on Mars, and the impact of low Martian gravity for regular and extreme sports. KSR can't even leave his convenient narrative trick of anti-aging alone, and embarks on a fully fleshed-out subplot digging into biological senescence and memory.
Inevitably, not all of this works, and I suspect readers will find themselves skim-reading the themes that don't interest them as much. For me, I couldn't care as much about political theory as KSR clearly does. But then I just couldn't get enough of the Red vs. Green tussles of Ann and Sax, or the scientific detail of Mars' animation, from global geoengineering to gardening its microclimates. And there's a great stretch where Nirgal, a first generation child, takes part in a solitary, round-the-world marathon (Mars-athon?), which really opened my eyes to seeing Mars as a (potential) physical, living-and-breathing place.
So almost impossible not to recommend to science fiction fans, but it's a real taskmaster of a trilogy of novels. But, I think, absolutely worth it.
