Far, far more than everything any man has ever wanted to know about his hair--and still featherweight. Flynn addresses this skimpy guide to men who are trying to prevent hair loss, but the bottom line takes just one sentence: ""Ninety percent of thinning heads experience a balding problem because their scalps are genetically programmed to do so""--and nothing can be done to stop that. Presumably for the other ten percent, then, Flynn offers some basic tips, well-padded with fluff (re hair texture, ""the American College Dictionary says fiber is 1. a fine threadlike piece, as of cotton; 2. a slender filament. . .""). Samples: ""What Kind of Hair Do You Have""; ""Stress and Your Hair""; how to shampoo (three pages of detailed instruction); ""Do You Dare Color Your Hair"" (go ahead, from alt-over color change, to simple frosting). Flynn readily admits that thinning hair doesn't respond to topically applied vitamins or other nostrums; overall good health is usually the route to so-called healthy hair. Enough substance here, maybe, fora short magazine article.