Ursula K. le Guin - Hainish Cycle series

1. Roccanon's World

A world shared by three native humanoid races - the cavern-dwelling Gdemiar, elvish Fiia, and warrior clan, Liuar - is suddenly invaded and conquered by a fleet of ships from the stars. Earth scientist Rocannon is on that world, and he sees his friends murdered and his spaceship destroyed. Marooned among alien peoples, he leads the battle to free this new world - and finds that legends grow around him even as he fights.

2. Planet of Exile

The Earth colony of Landin has been stranded on Werel for ten years--& ten of Werel's years are over 600 terrestrial years. The lonely & dwindling human settlement is beginning to feel the strain. Every winter--a season that lasts for 15 years--the Earthmen have neighbors: the humanoid hilfs, a nomadic people who only settle down for the cruel cold spell. The hilfs fear the Earthmen, whom they think of as witches & call the farborns. But hilfs & farborns have common enemies: the hordes of ravaging barbarians called gaals & eerie preying snow ghouls. Will they join forces or be annihilated?

3. City of Illusions

He was a fully grown man, alone in dense forest, with no trail to show where he had come from and no memory to tell who — or what — he was.
His eyes were not the eyes of a human.
The forest people took him in and raised him almost as a child, teaching him to speak, training him in forest lore, giving him all the knowledge they had. But they could not solve the riddle of his past, and at last he had to set out on a perilous quest to Es Toch, the City of the Shining, the Liars of Earth, the Enemy of Mankind.
There he would find his true self... and a universe of danger.

4. The Left Hand of Darkness

A groundbreaking work of science fiction, The Left Hand of Darkness tells the story of a lone human emissary to Winter, an alien world whose inhabitants can choose -and change - their gender. His goal is to facilitate Winter's inclusion in a growing intergalactic civilization. But to do so he must bridge the gulf between his own views and those of the completely dissimilar culture that he encounters.

5. The Dispossessed

Shevek, a brilliant physicist, decides to take action. He will seek answers, question the unquestionable, and attempt to tear down the walls of hatred that have isolated his planet of anarchists from the rest of the civilized universe. To do this dangerous task will mean giving up his family and possibly his life--Shevek must make the unprecedented journey to the utopian mother planet, Urras, to challenge the complex structures of life and living, and ignite the fires of change.

6. The Word for World is Forest

Centuries in the future, Terrans have established a logging colony & military base named "New Tahiti" on a tree-covered planet whose small, green-furred, big-eyed inhabitants have a culture centered on lucid dreaming. Terran greed spirals around native innocence & wisdom, overturning the ancient society.

Humans have learned interstellar travel from the Hainish (the origin-planet of all humanoid races, including Athsheans). Various planets have been expanding independently, but during the novel it's learned that the League of All Worlds has been formed. News arrives via an ansible, a new discovery. Previously they had been cut off, 27 light years from home.

The story occurs after The Dispossessed, where both the ansible & the League of Worlds are unrealised. Also well before Planet of Exile, where human settlers have learned to coexist. The 24th century has been suggested.

Terran colonists take over the planet locals call Athshe, meaning "forest," rather than "dirt," like their home planet Terra. They follow the 19th century model of colonization: felling trees, planting farms, digging mines & enslaving indigenous peoples. The natives are unequipped to comprehend this. They're a subsistence race who rely on the forests & have no cultural precedent for tyranny, slavery or war. The invaders take their land without resistance until one fatal act sets rebellion in motion & changes the people of both worlds forever.

7. Four Ways to Forgiveness

At the far end of our universe, on the twin planets of Werel and Yeowe, all humankind is divided into "assets" and "owners," tradition and liberation are at war, and freedom takes many forms. Here is a society as complex and troubled as any on our world, peopled with unforgettable characters struggling to become fully human. For the disgraced revolutionary Abberkam, the callow "space brat" Solly, the haughty soldier Teyeo, and the Ekumen historian and Hainish exile Havzhiva, freedom and duty both begin in the heart, and success as well as failure has its costs.

8. The Telling

Once a culturally rich world, the planet Aka has been utterly transformed by technology. Records of the past have been destroyed, and citizens are strictly monitored. But an official observer from Earth named Sutty has learned of a group of outcasts who live in the wilderness. They still believe in the ancient ways and still practice its lost religion - the Telling.

Intrigued by their beliefs, Sutty joins them on a sacred pilgrimage into the mountains...and into the dangerous terrain of her own heart, mind, and soul.