Tlön, Uqbar, Orbis Tertius is a short story by the 20th century Argentine writer Jorge Luis Borges. The story was first published in the Argentine journal Sur, May 1940. The "postscript" dated 1947 is intended to be anachronistic, set seven years in the future. The first English-language translation of the story was published in 1961.
In the story, an encyclopedia article about a mysterious country called Uqbar is the first indication of Orbis Tertius, a massive conspiracy of intellectuals to imagine (and thereby create) a world: Tlön. Relatively long for Borges (approximately 5,600 words), the story is a work of speculative fiction. One of the major themes of "Tlön, Uqbar, Orbis Tertius" is that ideas ultimately manifest themselves in the physical world and the story is generally viewed as a parabolic discussion of Berkeleian idealism — and to some degree as a protest against totalitarianism.
"Tlön, Uqbar..." has the structure of a detective fiction set in a world going mad. Although the story is quite short, it makes allusions to many leading intellectual figures both in Argentina and in the world at large, and takes up a number of themes more typical of a novel of ideas. Most of the ideas engaged are in the areas of language, epistemology, and literary criticism. (Wikipedia)