Hainish series

When the Athsheans, the inhabitants of a peaceful world, are conquered by the bloodthirsty Yumens, they retaliate against their captors, abandoning their rules against violence and endangering the very foundations of their society.

The Earth colony of Landinhas been stranded on the planet Werel for ten orbits, each of which is sixty Earth years long. As Werel once again enters its fifteen-year-long winter, the lonely and dwindling human settlement is joined by the nomadic hilfs, an indigenous humanoid people who only settle down for the cruel cold spell. The hilfs fear the Earthmen, whom they call farborns, regarding them as witches and avoiding interaction with them. Although

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A human emissary sent to the world of Winter to bring it into a galactic civilization must find a way to bridge the gulf between his outlook and that of the natives, who can change gender at will.