Here's another entry in the game of predicting what science and technology will come up with after the turn of the millennium, this one from a theoretical physicist. Kaku, author of Hyperspace (1994), defines his central thesis in a few words: We humans are about to make the transition ``from being passive observers of Nature to active choreographers of Nature.'' He forecasts major breakthroughs in three specific areas: computer science, molecular biology, and quantum physics. While all three of these disciplines have already had a significant impact on our daily lives, Kaku finds a broad consensus among scientists, many of whom believe that everything we have seen so far is merely a prelude to what lies in store. In particular, while the development to date of these areas of science has been marked by extreme specialization, the 21st century is likely to be an age of synergy, in which each area builds on the discoveries of the others. On a 20-year time frame, computer chips will become smaller, cheaper, and almost ubiquitous; genetic therapy will have cured many diseases, possibly including most cancers. But beyond that point, it appears that fundamental bottlenecks in both computer science and molecular biology will necessitate new breakthroughs, many of which will derive from quantum physics. This may fuel a new round of technological innovations, among them artificial intelligence (a robot in every home), tailor-made organisms (new foods and medicines), nanotechnology, and new energy sources. Kaku does not ignore the potential downside of these developments, examining such nightmare scenarios as robot killing machines fighting future wars and a revived eugenics movement. But if all goes well, says Kaku, we may well develop into a true planetary society, the first step toward making the entire universe our home. With this fascinating volume, Kaku positions himself as a worthy successor to the late Carl Sagan as a spokesman for the potential of science to revolutionize our lives. (Author tour) -- Copyright 1997, Kirkus Associates, LP. All rights reserved.