by Farrar, Straus and Giroux. $10.00. In this “natural history of obesity,” Ms. Beller has assembled reports of studies made in various countries and at various times on various aspects of fatness. By fitting together this originally scattered material, she has evolved a plausible explanation of obesity as a condition inherited from the Ice Age, when a layer of fat would have been useful insulation. She has also provided defensive weapons for butterballs tired of being called greedy or neurotic. She makes no pretense of offering a cure for what is not a disease in the first place, but does offer some tentative suggestions for coping with the condition. She also points out that shrinking fuel supplies may yet put the Venus of Willendorf back on her pedestal. Index, bibliography..