The author of Inside Intuition (1973), and Eloquent Animals (1978) is out of her element here. First off, Davis shuns a scientific definition of her subject, energy, in favor of such mystical phrases as ""energy is a body truth. . . a personal, internal experience""--and then speculates about its source in brain chemistry! She takes the trouble to identify four energy-types--sprinters, strollers, trotters, and hurdlers--on the basis of (surprise!) whether their energy is high, low, medium, or variable. And she picks and chooses studies to form opinions about everything from nutrition (""very few Americans are malnourished, except those who are too poor to afford fresh fruits and vegetables"") to weather: ""many people,"" we are told, ""would benefit from owning a negative-air-ion generator."" Of course, there are also some relatively sound tips about exercise or meditation--the bread-and-butter of self-help books. But to slosh through Louis Nizer's assurance that all the people ""of achievement"" he has ever known had a high energy level, or to watch Davis trying to distinguish between ""nervous energy"" and something called ""enerjoy""--well, the indiscretions and the incaution outweigh the occasional insights.