US fantasy fiction author Ursula K. Le Guin dies at 88

Ursula K. Le Guin, shown in this file photo from the 2014 National Book Awards, first found success with the publication in 1969 of "The Left Hand of Darkness"

US fantasy author Ursula K. Le Guin, one of the most famous female science fiction writers in history, has died, her family announced Tuesday. She was 88.

Le Guin became best known for her "Earthsea" series, which she began in the late 1960s, in which an apprentice sorcerer fights against the powers of evil, decades before Harry Potter did the same.

As well as novels she also wrote children's books, short stories, poetry and essays.

"The family of Ursula K. Le Guin is deeply saddened to announce her peaceful death yesterday afternoon," read a short statement on her verified Twitter account.

Best-selling American crime writer Stephen King mourned her as "one of the greats," in his own tribute on Twitter.

"Not just a science fiction writer; a literary icon. Godspeed into the galaxy," he wrote.

Educated at Radcliffe College, Massachusetts, and New York's Columbia University, Le Guin was a Fulbright Fellow in 1953 and an expert in anthropology. Her father Alfred Louis Kroeber was an ethnologist known for his work on Native Americans.

She published her first novel, "Rocannon's World," in 1966. But she first found success with the publication in 1969 of "The Left Hand of Darkness," which won a string of prizes and became a great science fiction classic.

The novel, the beginning of the Hainish Cycle which contains six other titles, broke with the sclerotic patterns of science fiction's golden age.

The planet on which "The Left Hand of Darkness" is based is little different from the Earth, except for its glacial climate, but the beings who populate it are radically different: they have only one sex and assume in turn masculine and feminine roles.

In the book she posed questions on sexual identity, and questions what social rules, culture and inner life such a world could exude.

"I tend to avoid fiction about dysfunctional urban middle-class people written in the present tense. This makes it hard to find a new novel, sometimes," she once said.

In her stories of galactic societies, Le Guin -- who said she was influenced by anarchist and Taoist thinking -- sought to prove there is no total and permanent solution, either in theology, politics or human science past or future.

"The only thing that makes life possible is permanent, intolerable uncertainty; not knowing what comes next," Le Guin said.

She was born on October 21, 1929 in Berkeley, California and later settled in Portland, Oregon in the northwestern United States.

She married historian Charles Le Guin, and the couple had three children.