This paper is designed as an information guide for those persons responsible for rearing human infants from birth to 18 months. The author provides an extensive review of the literature and trends of research in this area noting that the current volumes of knowledge in this area are not yet dependable enough to provide reliable bases for practice. He notes that among the problems presented in the study of infants are (1) availability of subjects in natural environment, and (2) the lack of reliable measures for research. Provided is an enumeration, explanation and evaluation of kinds of studies and known information about infant development. Included are longitudinal studies, cross-sectional studies, and assessments of direct and indirect evidence. The author feels that practitioners should demand and support the production of more dependable knowledge by sponsoring field and basic research throughout infancy on the whole infant (rather than on his separate behaviors) as he functions in real life. White admonishes practitioners to accept the fact that, for the time being, child-rearing practices must be designed on an admitted best guess basis. An extensive bibliography is provided. (Author/AJ)