One of the earliest cyberpunk works: a novella set in a world with a global immersive VR environment, rather like a sane version of "Snow Crash". Short but competently written, and impressively well-forecasted for 1981. Recommended. (Since it's a novella, it's sometimes hard to find; the ISBN link below is to a paperback edition along with some related essays that's often available second-hand.)
ISBN 0312862075. Buy this book at Amazon.