The Left Hand of Darkness (Hainish Cycle, #6)

Genly Ai is an Envoy, a diplomat sent to make first contact with inhabited planets. Winter, a world locked in a perpetual ice age, is a particularly daunting challenge: its people are androgynous, only taking on male or female sexual characteristics during ‘kemmer’, a monthly period of change and arousal. Struggling to understand the intricacies of a society where anyone could be both mother and father to multiple children, Genly is soon caught in the dangerous machinations of politicians and kings who care little for his life, or the potential life beyond their planet. He is left with little choice but to flee across a vast ice sheet, a journey dangerous enough for a native of Winter, let alone a human ill adapted to extreme cold. Yet with survival and desperation comes trust, and Genly gains a new understanding of Winter and its people.