A dense handbook of basic health care and recycled beauty-and-fashion hints. The longest section deals with exercise, care of eyes and teeth, sleep, cosmetic surgery (""think twice""), vitamin supplements, smoking (""even if you don't believe the doctor's warning. . .you may be convinced by. . .facts about smoking and your looks""), There is a seven-day diet ""developed by a nutritionist"" that doesn't always consider the high calorie/cholesterol count of many school lunch programs, and brief mention of anorexia and bulimia. ""Because You're a Girl"" describes Premenstrual Syndrome, Toxic Shock Syndrome, the Pap test, self breast-examination, and vaginitis. Also discussed: skin care and make-up, hair, clothes, care of hands and feet, accessories, perfumes. Though most of this information is available ad nauseam in monthly magazines for teen-agers, some readers might find it comforting to see it all in one non-glitzy volume. The language style of these magazines, though, persists: ""for that special look you're striving to create. . .buy pale white rosebuds to tuck behind an ear."" The health section, while cautious, would benefit from a more thorough listing of its sources of advice. For some, all this is old hat. For others, even reading about a ""soothing"" foot treatment made from avocados, lemon juice, and honey (""Slather it on"") and two whole pages about pearls can be not merely informative, but fun. Index.