The impact of urbanization, industrialization, and immigration on American children from the 1850's to the 1920's is examined. Specifically, child labor, schooling, growing up female in the industrial age, the juvenile justice system, and dependent children are discussed. Before 1900, child protection in all its manifestations was an informal affair handled by the local community through the families concerned. After the turn of the century professionals took over and institutions appeared. Schools inculcated appropriate social values, especially among the children of immigrants; reformatories re-formed the characters of wayward young people; and orphanages replaced lost families. But these simple approaches did not stem the rising tide of social misery suffered by children, and so during the Progressive era the entire system was transformed. The results included a remaking of the schools, the professionalization of social work, the founding of the juvenile court, the creation of a federal Children's Bureau, the definition and virtual elimination of a new social problem--child labor--and the emergence of national concern about the lives of future citizens. (RM)