Simulacron-3 (1964) (also published as Counterfeit World), by Daniel F. Galouye, is an American science fiction novel featuring an early literary description of a simulated reality.

[2] Simulacron-3 is the story of a virtual city (total environment simulator) for marketing research, developed by a scientist to reduce the need for opinion polls.

In writing, the Frederik Pohl short story "The Tunnel under the World" (1955) deals with similar philosophic themes and satirical criticism of marketing research, although in Pohl's story the described simulated reality is mechanical, an intricate scale-model whose inhabitants’ consciousnesses reside in a computer, rather than being solely electronic.

The Philip K. Dick story Time Out of Joint (1959) presents a man who is unaware that he is living his life in a physically simulated town until changes in his (apparent) reality begin to manifest themselves.

The novel has been adapted several times into other media, including as the two-part German television film World on a Wire (Welt am Draht, 1973), by Rainer Werner Fassbinder,[3][4] "staying reasonably faithful to Galouye's book," as the film The Thirteenth Floor (1999) produced by Roland Emmerich and directed by Josef Rusnak, and as a play World of Wires (2012) directed by Jay Scheib.