This report of family social class influences on children's characteristics is based on data from a longitudinal study of more than 1,000 children, black and white, of various social backgrounds. The sample was originally selected for another study (the St. Louis Baby Study) giving only secondary consideration to social factors. It includes a large number of lower-class black families and is not considered to be representative of the general American urban population. Data were collected from the mother, as general family informant and personal respondent, and from the child. Data on child and family cover the period from birth through the first year of school. Child characteristics include physical characteristics, scores on developmental measures, and scores on the Peabody Picture Vocabulary Test. Family factors include: family income, parental authority and role, number of siblings and size of household, paternal stability, maternal employment and age, parental education, and housing. Changes in maternal attitudes are also examined. The report differentiates between social class (its primary concern) and social status, attempting to keep parental occupational level, education and source of income conceptually distinct. The bulk of the volume consists of charts, tables and other background materials. Appendices include materials from an earlier report dealing with social class configurations of early childhood socialization. (BF)