Instead of describing ages-and-stages, tills new Gesell Institute handbook on sibling warfare tells parents just what they can do ""to make life at home with their children more harmonious, more comfortable."" The advice, moreover, is nearly all drawn from previously published (and scrupulously credited) sources: How to Grandparent (Dodson), Couples with Children (Wilson and DeLuca), Why Your Child is Hyperactive (Feingold), Raising Siblings (Carradine and Carradine), etc. It all comes down to ""ignore, separate, be calm, exhibit vast patience""--illustrated with appropriate anecdotes that won't, however, be much help when parents are caught on the front lines of sibling warfare. Even more dubious are sections on body types (ecto-, endo-, and mesomorphs) as determiners of temperament, and on the effects of birth order--both of which are carefully laid out only to be demolished: ""any attempt to predict intersibling behavior from them must be a vast oversimplification."" True to the customary Gesell practice, the authors do provide a year-by-year account of what to expect in terms of sibling relationships: ""possibly Eleven-year-olds and Six-year-olds make the very worst combinations""; ""Three's reaction to a baby sib depends largely on his own individuality."" A disappointing offering from a usually authoritative source.