Once upon a time, science fiction was only in the future. It was the stuff of drive-ins and cheap double-bills. Then, with the ever-increasing rush of new, society-altering technologies, science fiction pushed its way to the present, and it busted out of the genre ghetto of science fiction and barged its way into the mainstream. What used to be mere fantasy (trips to the moon? Wristwatch radios? Supercomputers capable of learning?) are now everyday reality. Whether nostalgic for the future or fast-forwarding to the present, this guide covers an enormous range of sci-fi.