->''"Light is the left hand of darkness\\
and darkness is the right hand of light.\\
Two are one, life and death, lying\\
together like lovers in kemmer, \\
like hands joined together,\\
like the end and the way."''

A 1969 Science fiction novel from UrsulaKLeGuin telling the story of Genly Ai of Earth, the Envoy of the [[TheFederation Ekumen]], to the planet Gethen. Gethen is far away from the rest of the planets humans were settled on by the ancient [[{{Precursors}} Hain]]. Gethen, which has been nicknamed by Terrans Winter, is a cold, glacial planet, but its real peculiarity is in the people: Gethenians are [[GenderBender Gender Benders]], and it has a profound effect on their society.

Genly Ai's task is to persuade Gethenians to join the Ekumen, but they're unreceptive, while tensions between the nations of Orgoreyn and Karhide grow and the first war ever on Gethen is looming on the horizon...

!!Tropes appearing in ''TheLeftHandOfDarkness'':

* AlternativeCalendar: Karhide uses a calendar in which the current year is always "Year One", with only years before and after being numerated. It ''is'' a bit problematic, thus they refer to well-known events (like kings' ascension to throne) to record history. The followers of Yomeshta religion, however, have a calendar of the usual type.
* {{Asexuality}}: Gethenians when not in kemmer are not only sex/gender-neutral, but also effectively asexual - and only about 1/4 of (adult) life is spent in kemmer. Kemmer, on the other hand, is a rather [[MateOrDie more desperate state]] than humans normally experience, to the point where it automatically gets you off work.
* DeliberateValuesDissonance: Gethenians see no problem with [[BrotherSisterIncest sibling-sibling incest]] - while in "kemmer" a Gethenian is in an almost-MateOrDie situation, so they're forgiving when you're a horny teenager and the only also-in-kemmer person around is your sibling (though [[SingleTargetSexuality monogamous incest]] is seen just as we see it, and the lovers are expected to part ways when the first kid appears). On the other hand, theft is a horrible crime, since on an IceWorld you may just be sentencing someone to death by starvation, and a suicide is seen with distaste as a kind of cowardice, an act of refusal to face reality.
** On a personal level, Genly considering some things feminine in a rather derogatory way (see for example MultitaskedConversation below). Le Guin is a well-known feminist, and the main character remains sympathetic rather than being a StrawMisogynist.
* DoesThisRemindYouOfAnything: Tibe's heavily broadcast [[AdolfHitler rants against foreigners]] etc., and his [[JosephStalin sneaky ascent]] against Estraven.
* EvilChancellor: [[ZigZaggedTrope Zigzagged]]. At first, the Chancellor is a decent [[strike:guy]] [[GenderNeutralWriting person]] serving the insane King, but is soon replaced by a properly evil one. Of course, both the insane king and Genly initially think Estraven is evil.
* EnigmaticMinion: Genly's view of Estraven is pretty close to this for most of the book
* {{Exposition}}: done through {{fictional document}}s on Gethenian society or transcripts of local legends, and {{inner monologue}} of Genly.
* [[FantasticRacism Fantastic Sexism]]: The Gethenians' reaction to Genly's permanent maleness, and, conversely, his reaction to their gender bending. Some Gethenians ''are'' permanently male or female, but this is regarded much as intersex conditions typically are in our society - worse, in fact, since generally more obvious.
** Such "perverts" do however play an essential role in the Handdara religion due to their role in foretelling, as do the mentally ill: a Handdaran foretelling is made by a [[RagtagBunchOfMisfits group of nine]] which includes "perverts", celibates, "zanies", at least one person in kemmer, and the "weaver", who joins their psychic energy together.
* [[FireForgedFriends Ice Trek Forged Friends]]: Genly and Estraven.
* FirstContact: Genly is not the first alien on Gethen (the Ekumen always sends explorers first, where possible), but he ''is'' the first official one, and the first envoy, complete with, yes, IComeInPeace and TakeMeToYourLeader, both of which get rather... complicated by the local reception.
* GenderBender: Gethenians have a 26-day long cycle of going into heat ("kemmer") and spending the rest as asexuals. Which sex they assume is beyond their control, though the use of artificial chemical means is implied to be on the rise.
* GenderNeutralWriting: Much pain to anyone not a Gethenian. Sooner or later they all decide to use "he" or "she" for convenience, though it leads to traps - Genly's feminine "landlady", whom he couldn't resist to think of as a woman, was a father several times and a mother not once.
** On the other hand, Gethenians have no proper word for man/woman, so outsiders attempting to make themselves understood must use the words that refer to the male and female forms of kemmer (the only alternative being words for male and female animals). In other words, they can only make the sex/gender distinctions humans routinely use by thinking of them as animals in permanent heat. This creates a few difficulties for Genly.
* GodSaveUsFromTheQueen: with a few twists, quite apart from the [[GenderBender obvious one]]; Argaven is also, for the most part, sufficiently bonkers to qualify as a version of TheCaligula.
* TheGreatEscape
* TheGulag: Orgoreyn runs them. Gulag - "[[ReassignedToAntarctica send them to Siberia!]]" - the planet [[ExactlyWhatItSaysOnTheTin Winter]] - [[IncrediblyLamePun get it]]? Wink, wink?
* [[HerHeartWillGoOn His/Her Heart Will Go On]]: It's complicated.
* HeroicSacrifice: particularly notable as Gethenians very much frown on suicidal behaviour.
* HumansArePsychicInTheFuture
* IceWorld: Gethen is currently in its Ice Age.
* IkeaErotica: Most of the discussion of Gethenian sexuality; justified in that these are generally anthropological in intent. Also Genly's speculation about the possibility of intercourse with a Gethenian.
* IncestIsRelative: [[spoiler: Estraven]] and Arek.
* InfoDump: the [[{{Exposition}} expository chapters]] may feel like one.
* TheKingdom: Karhide.
* LanguageOfTruth: Mindspeak.
* LoveMartyr: Estraven's poor ex.
* MathematiciansAnswer / EitherOrProphecy: Some of the drawbacks of Handarran foretelling. Apparently, this is the ''point''.
* MedievalStasis: Gethenians have known radio and electric automobiles for two thousand years, and they still use them. It's discussed in-universe whether it's the need to survive in harsh environment that uses up all the innovativeness.
* MultitaskedConversation: The Karhideans do this a lot, largely due to their complicated ''shifgrethor'' status system, much to Genly's frustration, since he finds the DoubleSpeak involved [[UnfortunateImplications troublingly feminine and shifty.]] The Orgota for their part tend towards this because they live in a police state.
* NoBiologicalSex: The Gethenians, when they're not in kemmer.
* [[OhMyGods Oh My Meshe]]: Yomeshta tend to use expletives involving their prophet, Meshe.
* TheRepublic: Orgoreyn, which is a PoliceState.
* PerfectPacifistPeople: Sort of. Gethenians do kill each other by murders or clan feuds, but have never had a war. Like in the MedievalStasis example, it's discussed if it's the harsh weather, or the lack of male-female -- the most primal kind of "us versus them" -- distinction. [[spoiler:Later short stories reveal that the war will happen.]]
* ShownTheirWork: [[UrsulaKLeGuin le Guin]]'s interest in Taoism fairly clearly colours the descriptions of Gethenian religion, at least as far as Handdara is concerned: it is less clear what the breakaway Yomeshta group (dominant in Orgoreyn, and increasingly in Karhide) corresponds to, but at least it's a founder religion like Islam or Buddhism.
* SmugSnake: Argaven's PerpetualSmiler evil cousin Tibe, with a side of TheStarscream (though s/he finds it convenient to leave Argaven officially in charge).
* SomeoneToRememberHimBy: It's complicated.
* SubspaceAnsible: The Hainish Cycle, of which ''TheLeftHandOfDarkness'' is the most acclaimed part, is the TropeNamer, if not the TropeMaker.
* SuddenlyEthnicity: It can take a while to register that Genly is black.
* {{Telepathy}}: The peoples of the Ekumen have learnt to use this (which makes them TelepathicSpacemen to the Gethenians). The Gethenians have not, though it's clear they are capable of learning (as are humans, such as Genly).
* {{UST}}: Genly and Estraven, [[DiscussedTrope discussed]] in-universe.
-->"For it seemed to me, and I think to him, that it was from that [[{{UST}} sexual tension]] between us, admitted now and understood, but not assuaged, that the great and sudden assurance of friendship between us rose: a friendship so much needed by us both in our exile, and [[FireForgedFriends already so well proved in the days and nights of our bitter journey]], that it might as well be called, now as later, [[LoveEpiphany love]]. But it was from the [[InterspeciesRomance differences between us]], not from the affinities and likenesses, but from the difference, that that love came: and it was itself the bridge, the only bridge, across what divided us. For us to meet sexually would be for us to [[BoldlyComing meet once more as aliens]]. We had touched, in the only way we could touch. We left it at that. [[TearJerker I do not know if we were right.]]"
* TheVamp: Orgota SecretPolice agent Gaum, complete with attempted HoneyTrap.