The concept of fuzzy logic has been surfacing as the wave of the future on the business pages and in articles on Japan. Fuzzy designs, science/computer-writers McNeill and Freiberger tell us, are generating self-parking cars, intelligent TVs and VCRs, and self-adjusting vacuum cleaners; eventually, they will enable computers really to read, listen, and talk back. That's the bright side. The dark side is the view of many academics and entrepreneurs--whose careers and companies are based on ``crisp'' logic--that statement A and its denial, not-A, cannot both be true: ``A sheep cannot be both white and non-white.'' In fuzzy logic, though, sheep can be both or neither. It's a matter of degree along a continuum. Once you start thinking this way, it's clear that language itself is fuzzy, full of gray areas of ``more or less.'' This idea has given rise to a theory of sets and subsets with varying degrees of membership--which in turn has yielded a theory and proofs that have enabled innovators to devise circuits or collections of if-then statements that can be programmed into chips to make decisions in controlling a variety of processes, from purifying water to diagnosing disease. The authors enthuse and argue about fuzzy logic, providing a history of movers and shakers like Lotfi Zadeh and Bart Kosko. To their credit, they also present the loyal opposition. The big issue is that, while the ideas originated in America, Japan has lapped them up, not only to make supertrains run superbly but to do all of the tricks above and more to come. Will the US catch on? Maybe, the authors suggest, but we'll still be playing catch up. Part of the problem is the paucity of books on the subject. This one, while fuzzy in details, at least serves to introduce readers to the concepts and a dazzling cast of characters.