The Left Hand of Darkness by Ursula K Le Guin

Another classic SF novel for the Grognard book club. 

In this one, Genly Ai is sent as an envoy to the planet of Gethen to recruit them to the interstellar confederation of planets known as the Ekumen. Gethen is unusual in that the people are ambisexual with no fixed gender for most of the time, except for two days in the month where they express as either male or female, and form intense relationships. This has profound effects on their society that Genly struggles to understand as he navigates the political and social mine field of the rivalry between the countries of Karhide - a kingdom, and Orgoreyn - a repressive police state, trying to negotiate a treaty. His first point of contact is with the prime minister of Karhide who is called Estraven, and is seeming acting with motives of his own following an intricate code of conduct known as shifgrethor,

I found this book difficult to get into initially, as even more than with Dune as large number of strange names, places and concepts are thrown at the reader without the aid of a glossary or a map to follow. The chapters alternate between the view point of Genly, Estraven and short extracts of folk lore and history that illustrate the nature of Gethen society. Sticking with the story pays off though, even though it is still sometimes confusing when characters have different names (or even the same one as a historical character from one of the folk tales). It all makes sense in the end though.

The main conceit of the book is that people are free from sex drives for most of the time, which in Le Guin's carefully constructed thought experiment has resulted in war and rape being unknown, although societies are still capable of repressive behaviour. It is not uncommon for Gethens to experience both sides of parenthood in their lives, leading to the classic line "The King Was Pregnant". 

If this book was written now, I wonder if Le Guin would have chosen a different default pronoun - all characters are referred to as 'he', although arguably this shows the default assumption of the main protagonist in the way he deals with the Gethens. The political machinations are also well done, although motivations are complex. 

Definitely worthy of the status this book has, and I'm looking forward to discussing it