Not a quick easy read but well worth the effort.
From Amazon: The fact that this series is not in print is almost criminal, probably because Aldiss is British or something. But for those who haven't heard of perhaps the greatest science-fiction series ever to be written, the Heliconnia series was Aldiss' attempt at a world building on the scale of Dune, but at the same time using it to make a commentary on his feelings about current society. Lofty goals but the beauty of it is that it never feels like he's overextending himself, everything feels natural and the book never deviates from Aldiss' calm, almost Arthur Clarke like narration, though his use of metaphor is much better than the more hard science oriented Clarke. For those coming in late, Aldiss envisioned Heliconnia as a Earth like planet with one big difference, really really really long seasons. The planet takes about 2500 years to orbit so each generation effectively notices only one season. In the first book he shows the end of winter and the reawakening of civilization, a cycle that has gone by many times without anyone realizing it. In the beginning the book is almost standard Tolkein stuff, fantasy but just when you think that Aldiss has gone into sword and sorcery, it throws in a bit with Earth having set up an orbiting space station to watch the planet, reminding you that above all this is a science-fiction story. If you can find even one book of this series used, snap it up as fast as you can, or just swamp a publisher with requests to put it back into print. Like Moorcock's Cornelius series, this is one that deserves to be out there for everyone to read.
Helliconia is a planet in a binary star system which causes seasons to last for hundreds of generations. It makes for a good plot and the book is well written, but the characters were all far too wrapped up in themselves and hardly seemed to notice the changes on their planet. It made the plotline, which was not bad in its own right, seem out of place.