On 12 August 2010 Gollancz are reissuing Brian Aldiss' colossal Helliconia Trilogy in one omnibus volume, simply entitled Helliconia.
The trilogy was originally published as three volumes, Helliconia Spring (1982), Helliconia Summer (1983) and Helliconia Winter (1985). When asked about the absence of autumn, Aldiss replied that he wasn't Vivaldi and he felt that three books was enough to explore his ideas. When he conceived of the idea of a single trilogy exploring one planet, Aldiss realised that the planet would have to be vigorously researched and mobilised many of his contacts in multiple disciplines at Oxford University for advice on geography, biology, geology and orbital mechanics, amongst other areas, resulting in a world remarkable for its depth and detail.
The trilogy, which commences some six thousand years in our future, spans thousands of years in the history of Helliconia, an Earth-like world which has a complex life-cycle stemming from its position in a binary star system. Helliconia orbits Batalix, an orange dwarf, which in turn orbits Freyr, a blue supergiant one thousand light-years from Earth. It takes over 2,500 years for a 'Great Year', a full orbit of Batalix around Freyr, to be completed. When Helliconia is furthest from Freyr, the planet becomes a frozen icefield, whilst at its closest the entire planet is baked in heat and the equatorial belt becomes uninhabitable. As the Great Years pass the planet is locked in a Darwinian battle between two species, a humanoid-like race which thrives in the summer but wanes in the winter, and the ice-loving phagors. Events on Helliconia are observed by an orbital space station from Earth, and a minor subplot has the crew of the station debating on whether or not to interfere with events on Helliconia.
The Helliconia Trilogy is one of science fiction's most outstanding achievements, with the world of Helliconia representing the pinnacle of SF worldbuilding to date (far exceeding, in my opinion, Frank Herbert's Arrakis and only really being challenged by Kim Stanley Robinson's Mars, although the latter has the advantage of actually existing). Its return to print is great news, and I will be re-reading and re-reviewing the trilogy later this year.