"Most of us would like to be smarter," asserts Restak (The Brain, companion to PBS's series by the same name), neuropsychiatrist and clinical professor of neurology at George Washington University Medical Center. Restak claims that improving cognition is the answer. In accessible science-teacher style, Restak delineates the brain's attributes, from its weight (three pounds) to the number of nerve cells (100 billion) and its infinity of synapses, explaining what aids communication, informs memory and so forth. Knowing how the brain works is important to building its power, says Restak, and in this high-tech age, we need as much cognition as we can get. He proposes a comprehensive and handy plan to improve one's mind, literally as well as literarily. If one stops learning, one's overall mental capacity diminishes because the synaptic links shrink. Brain stimulation has been declared protection against Alzheimer's. The brain does not age; keeping it "fit" is no more difficult than keeping one's cholesterol under control. In outlining a plan including everything from exercise to learning to play a musical instrument, Restak explains how interconnections between the brain's functions keep it growing. Train your brain through logic problems, complicated games like chess, difficult jigsaw puzzles and widely varied reading. Not surprisingly, watching TV, a passive act, does exactly what your mother always said it did makes you stupid. The extraordinary range of references to literature, science, gamesmanship and even cryptograms makes it apparent that Restak practices what he preaches. This unusual, intriguing book will appeal to the health diligent and the senior contingent.