William Gibson wrote Neuromancer, the novel that coined the word cyberspace as most people now understand it, on a manual portable typewriter. He's said plainly that he had never so much as touched a computer while writing it.

The Direct Answer
On a manual portable typewriter, having never used a computer.
Neuromancer went on to win the Hugo, Nebula, and Philip K. Dick Awards in 1984 and 1985, the only novel ever to take all three.

Writing the Future Without the Hardware

Gibson had first used the word cyberspace in his 1982 short story Burning Chrome, then built an entire novel and aesthetic around it in Neuromancer two years later. He did this with no real technical grounding in how computers or networks actually worked. When an interviewer later asked about the bulletin board jargon scattered through the book, Gibson said he'd never touched a PC while writing it.

What that gap did for the novel is easy to underrate. Gibson cared about what information does to power, money, and the body once it becomes the thing worth stealing, and he skipped straight to the human consequences instead of the engineering. The technology in Neuromancer reads as vivid and specific decades later even though very little of it describes how real computers work.

A Career Made on One Sweep

Neuromancer won the Hugo Award, the Nebula Award, and the Philip K. Dick Award, a combination no other novel has managed before or since. It's often called science fiction's triple crown. Gibson achieved it as a first time novelist working from a typewriter he later described as the kind of machine Hemingway might have used in the field, with royalties from the book eventually funding his first computer, an Apple IIc.

To see how that same instinct for atmosphere over accuracy shows up in his daily writing habits, from his revision process to his belief in naps, read the complete William Gibson writing routine.

What You Can Steal