When Hollywood wants a futuristic, paranoid thriller where nothing is what it seems, the studios reach for the work of one man. This week, Philip K. Dick continues his reign as Hollywood's idea spigot, with a remake of Total Recall. More PKD films are in the works, and there's no shortage of material out there.

Many science fiction books imagine strange new worlds — but only a few science fiction books have actually changed the world we live in. A few visionary authors have managed to make such an impression that they left the world a vastly different place.

A group of idealistic young hackers and computer whizzes exposes all of the government's secrets - sound familiar? It's the plot of John Brunner's 1975 novel, Shockwave Rider, which some are calling a precursor to Wikileaks.

Science fiction is the literature of our times, the fuel of our imaginations and the source of our favorite imaginary worlds. But what do we mean when we talk about "science fiction?" Here are some of the many definitions.

Somehow, John Brunner's 1969 Hugo winner has fallen out of print. That's a terrific shame, because Stand on Zanzibar is maybe the smartest, most engrossing piece of fiction I've read all year.

Science fiction doesn't just glimpse the future - it invents the scientific vocabulary of the present, according to an editor from the Oxford English Dictionary, who's listed nine scientific terms that came from science fiction.