The unusual part of this encyclopedic book sponsored by the Johnson & Johnson Company is the section on play: an exhaustive repository of suggestions for games and homemade toys, furniture, books, and musical instruments. . . all in the service of ""toddlerhood."" The rest of the volume--Growth and Development (feeding, talking, sleeping) and Personality and Behavior (discipline, fears, working mothers)--overlaps considerably with Dr. Spock and, especially, the Princeton Center's fine Second Twelve Months of Life. The advice is uneven. Suggestions for weaning, for example, are overly vague, while learning to talk is discussed in great detail--though the authors admit that ""it generally does more harm than good to worry about a toddler's speech."" The authors' guiding principle may also strike some parents as misguided: saying no is pretty much a no-no; distracting a child or reasoning are advised instead. Some of the information, moreover, seems outdated: the question of innate sexual differences in behavior is glossed over and an inborn taste for sweets is denied--in both cases, contrary to recent studies. There are, however, half a dozen variations of hide and seek--for youngsters who need lots of distraction.