This lengthy work should be subtitled ""In Praise of the Right Hemisphere"" since so much of it is devoted to the dextrous half-brain. Fincher's point is that what Western society deems intelligent is the rational, verbal, symbol-handling abilities, related to the speech center found in the left brain of most adults. The right side handles the Big Picture, dreams, the unconscious, music, spatial relations. It is integrative and creative in art and athletics. Thus he suggests that our intelligence tests are intrinsically skewed, even if they weren't biased by the samples used to establish IQ norms. All this is interesting but overemphasized. A book on such a vast subject should discuss what is known about memory, perceptual processing, problem-solving, etc. Instead there is a useful but overlong discussion of IQ tests (including very fair treatment of the Jensen controversy). There is a flashy and negative assessment of drugs as instant roads to braininess, but a definite endorsement of biofeedback. Later chapters discuss mental retardates and gifted individuals, or else speculate about male-female differences, machine intelligence, chimpanzee speech or the future of the human intellect. These sections all raise more questions than they answer so that the reader, in spite of the author's enthusiasm and generally lucid style, is left puzzled. What does seem clear is that we still don't know enough to define, much less measure, whatever is meant by human intelligence.