There are many flavours to science fiction, something that omnivorous readers adore and sceptics of sci-fi forget. Not all science fiction is Star Wars (which is arguably science fantasy), with action heroes, fast ships, and big guns (or, you know, swords). Not that there's anything wrong with those stories—but those who pan The Left Hand of Darkness for lacking such things tend to miss the point. It's not supposed to be like those stories; instead, it is a highly-faceted intellectual gem.
So much science fiction and fantasy takes either a contemporary or past form of society and transposes it to a futuristic or medieval time period, tweaks the names of people, places, and weapons, and calls it a Story. Again, this model isn't inherently wrong, but really great science fiction asks the question, "Well, what would humanity and human society be like if this were different?" and rebuilds society from the ground up to find an answer. This edition comes with a short introduction from Ursula K. Le Guin wherein she compares science fiction to a thought experiment. She's correct, and The Left Hand of Darkness is a shining exemplar of such an experiment.
There are two major factors that have altered Gethenian society: Gethen's harsh environment and the hermaphroditic nature of Gethenians. Le Guin investigates the consequences of both of these factors from the point of view of a man much like us, Terran Genly Ai.
The planet Gethen—idiosyncratically called Winter by the first Ekumen Investigators—has a far colder climate than temperate worlds like Earth. Additionally, its biosphere isn't very diverse, with little variety in plant or animal life. As Genly puts it: "it's extraordinary that you arrived at any concept of evolution, faced with that unbridgeable gap between yourselves and the lower animals." The Gethenians are, aside from their sexual differences, physiologically human, but they have adapted to survive the harsh and often deadly environment offered by Gethen. The constant need to survive, even in the middle of civilized cities like Erhenrang or Mishnory, is just as different from us as any differences in sexuality. For one thing, it seems to have stunted nation-building; war is less attractive when winter (and even summer) preys upon one's people. However, the hesitation to engage in open conflict may also be a result of shifgrethor, which I'll discuss later.
Of course, far more than the environment of Gethen, the most well-known part of The Left Hand of Darkness is the ambisexuality of the Gethenians. I won't belabour an explanation, since you should probably be familiar with the concept: the Gethenians are gender neutral for most of the month, then enter kemmer (estrus) and become either male or female, with the corresponding sexual organs coming to prominence, depending on hormones. So sex doesn't have the same impact it does on our society, as the Gethenians have no sex drive for the majority of their lives. In part, I suspect it led to the development of shifgrethor; moreover, it's affected how Gethenians view sexuality itself. For instance, incest has fewer restrictions on Gethen. Although monogamy exists, it is not enforced. Finally, the lack of permanent gender means gender roles themselves are nonexistent. This last reason has caused feminists (or anyone involved in issues of gender equality) to pay a lot of attention to The Left Hand of Darkness. I doubt I could truly discuss the subject any better than others already have, so go read their opinions instead. I'll just say I found the theme of gender equality definitely fascinating.
More fascinating, though, is the concept of shifgrethor, which Le Guin never fully explains. Probably it was difficult, since she designed it to be an intentionally alien cultural element. According to Estraven, the word itself comes from an old word for shadow; Genly calls it "prestige, face, place, the pride-relationship, the untranslatable and all-important principle of social authority." Shifgrethor fills the vacuum in society where socialized gender roles and the sex drive hold sway in our cultures.
After all, a huge portion of society revolves around trying to have sex. Members of both sexes spend a good deal of their time trying to impress members of the opposite sex—or their own sex—or entice others to impress them. Advertisers sell products designed to enhance sexual pleasure. Even products not primarily designed for that purpose, such as cars, tend to be advertised in a way that implies your sex life will improve if you buy the product. We are constantly consciously and unconsciously assessing and adjusting our attitudes to take into account the sex and gender of those around us.
The Gethenians don't have any of that. The makers of Axe bodyspray would need to adopt an entirely new marketing strategy for Gethen (although I'm sure their commercials will be just as annoying)! Yet every society needs standards of conduct, guidelines by which the "game" proceeds. Since Gethenians can't react to each other based on notions of masculine and feminine, they use shifgrethor instead.
I've discussed the themes of The Left Hand of Darkness at length; anyone still reading this review may be wondering if I'll ever talk about, oh, the characters or the story. Never fear! However, I saved these for last because they're the least fulfilling parts of the book. The characters are often two-dimensional; only Estraven and Genly Ai really develop beyond their role as plot devices. The story, likewise, is more overtly a vehicle for Le Guin's thought experiment than it is in other, more action-orientated science fiction.
Genly Ai is the Ekumen's First Envoy to Gethen, a sort of prelude to an ambassador. The Ekumen's custom is to initiate First Contact after a lengthy period of investigation by undercover Investigators. The First Envoy comes alone, as a curiosity rather than a threat. Genly's experience on Gethen emphasizes how dangerous the mission of a First Envoy can be, and also one of the reasons the First Envoy comes alone: he's expected to form a personal relationship with the world rather than just a political one. As the only person on the planet "constantly in rut," as the Gethenians put it, he's also even more alone than most Envoys. The effects of Genly's time on Gethen, from his quizzical reception in Kargide to his trek across the glaciated landscape with Estraven, finally register on the reader when he looks upon his crew mates as they emerge from their spaceship. To them, preserved in stasis while he works on the planet below, it's only been weeks. To him, it's been nearly three years, three years of living with people who have no concept of gender. He experiences reverse culture shock and admits that it's difficult to adjust to what he once considered normal.
The other character with some development is Therem Harth rem ir Estraven. As the book begins, we find him putting Genly in a difficult position, essentially abandoning the First Envoy to the mercy of the unstable King Argaven. Later it becomes clear that Estraven was acting in Genly's best interests, as he already knew that Argaven would soon banish him from the kingdom of Kargide. Due to cultural differences, such as the alien nature of shifgrethor, Estraven's motives aren't always as apparent to Genly as Estraven believes they should be; he laments this thoroughly, and it galvanizes him to go and rescue Genly from a forced labour camp. In their subsequent months spent in environmental isolation as they trek across the ice, both Genly and Estraven feel utterly alone: Genly owing to his obvious anatomical and cultural differences, and Estraven owing to his banishment from Kargide. As the two come to depend upon each other for survival, and even just basic human interaction, Estraven becomes our window into Gethenian culture.
The Left Hand of Darkness is also a tale of first contact. Genly Ai represents the Ekumen, a loose federation of worlds based on economic and spiritual fulfilment rather than any goal toward political unifications. Le Guin has limited space travel to relativistic speeds only but allows worlds to communicate ideas faster-than-light through a device known as an ansible. (It's a measure of Le Guin's influence on the field that other science fiction authors, famous in their own right, have adopted the ansible as a communications device in their works.) As a result, physical travel between worlds is inconvenient at best. Le Guin has a very poignant way of driving home the true impact of relativistic travel: Genly Ai has only been away from Earth for seven years, but 120 years have passed on Earth during that time—everyone he knew is dead. Even if one doesn't understand the physics involved, such consequences make clear the challenges space travel presents.
The most curious and interesting parts of The Left Hand of Darkness are sociological. There's a little adventure, I suppose, but that's not the main aim of the story, and as I said at the beginning of the review, that's the point. Although this is not a dense work of fiction, either in length or in the complexity of its ideas, it is a worthwhile one if you need something to make you think. And that's what makes books great, no? They make you think, challenge your own pre-conceptions, and reconsider the nature of our universe. It's all well and good to read a book just for a little entertainment, a little recreation. Sometimes, though, you want to go deep. The Left Hand of Darkness will take you on a journey: "in the beginning there was nothing but ice and the sun."