In this book, Dr. Warren summarizes and interprets the research literature on infants and children with visual impairments. He concludes that many aspects of delayed development are not the result of visual impairment itself, but rather of environmental variables that tend to accompany visual impairment. Thus, many of the typical developmental prdelays may be ameliorated or avoided by the appropriate structuring of the child's experiences. The author makes the argument that the goal of research in this area should be to understand the causes of variation within the population of visually impaired children, rather than making direct, developmental comparison with sighted children. Thus, the existing research literature is searched for evidence of variables that may account for individual differences, including particularly variables related to the child's multiple environments.