This book on the growth of word meaning in children focuses on the development of the appreciation of the relations that exist among twenty selected words as the individual matures from childhood through adolescence to adulthood. The four preconceptions which determined the experimental tasks, the set of words used, and the methods of analysis were: (1) Words contain meaning which is represented to a large extent by certain specifiable features; (2) Words cohere in a system in which word features can often be cast in a hierarchical or nest-like relation; (3) Context is an important factor in determining word meaning; and (4) The word, as a social phenomenon, is part of the culture and is relatively useless unless it means the same thing to different speakers of the language. In conducting the study, the author employed various types of experiments, including free-recall, free-association, and concept-formation tasks. In general, results supported the author's hypothesis that development proceeds from the concrete to the abstract, but difficulties for this "generalization theory" are seen to exist in certain aspects of child language. (FWB)