Tunnel Under The World - Frederik Pohl - Bog

"What is real? How do you define 'real'? If you're talking about what you can feel, what you can smell, what you can taste and see, then 'real' is simply electrical signals interpreted by your brain." Morpheus
Tunnel under the World is one of the first examples of the cyberpunk science fiction genre. First published in 1955, the story has been adapted for several media including "Virtual Nightmare", a made-for-TV horror film produced in 2000.
The novel deals with the concept of simulated reality, the hypothesis that reality could be simulated--for example by computer simulation--to a degree indistinguishable from "true" reality. It could contain conscious minds which may or may not be fully aware that they are living inside a simulation.
The novel has inspired many science fiction and screenplay writers appearing among others in a 1956 radio adaptation broadcast as an episode of X Minus One, was produced by the BBC as a 1966 series 2 episode of the anthology series Out of the Unknown and formed the basis for the Italian surrealist film, Il tunnel sotto il mondo (1969).
The novel has also inspired the screen script of the "Special Service" episode of The Twilight Zone and the development of the spec script of the 1998 American satirical comedy-drama film The Truman Show.