##Helliconia Spring by Brian Aldiss
Rating: ★★★★
The Helliconia series is set on a planet in a binary star system. The planet orbits a sun which in turn orbits another sun. The result of this is that the planet is exposed to a strange seasonal cycle as it approaches and moves away from the central sun, with both a 'small year' of 480 days and a 'long year' of over 2,500 Earth years.
This information is fairly key to understanding what Helliconia's all about. The 'long year' corresponds to a cycle of civilisation on Helliconia, where an offshoot of humanity dominates in the summer years, and a strange race known as the Phagors or ancipitals dominate in the winter. Helliconia Spring, in a narrative spanning several generations of human life, documents the transition from the cold winter of ancipital rule to the rise of human civilisation. We go from nomadic hunters and withdrawn populations to hunters based in the ruins of old civilisations, to a flourishing monarchic city-state.
Despite this somewhat historic scope, Aldiss doesn't do bad at making you connect with the characters, writing believable human interactions against the barbarous backdrop of a hostile, mostly-frozen planet. There is a clear familial narrative here in the same vein as 100 Years of Solitude, though not quite so magical. I was particularly pleased to see that Aldiss doesn't fall prey to naive interpretations of lifespan estimates (though checking this involved me calculating the odd Helliconian seconds-minutes-days-years ratio to find out how old characters would be on Earth), that successful characters aren't always good ones by our standard -- indeed, there are plenty of heartless moments -- and that he pays attention to the often-neglected half of humanity.
Similarly, Aldiss doesn't skimp on his biology, particularly paying attention to the ecosystems supporting the state of the world, and the changes which move through those ecosystems now the world is starting to slowly heat up. Rich descriptions of strange flora and fauna, and even of the alien perceptive ability of the ancipitals.
This is a seriously impressive piece of carefully thought-out science fiction, and I'm very interested to see where the rest of the trilogy takes it. Science fiction fans will probably like it, but also historians. Even readers of the grimmer, more realistic fantasy subgenres may find something to enjoy here.