This report describes an experimental day care program in Amsterdam, begun in 1969 to investigate how a day care center could contribute towards the favorable development of children under four from unskilled and semiskilled families. Because it is only recently that day care for children under four has been used to any extent, this is the first project in the Netherlands that is collecting psychometric data on young children which will form the basis for further research. Included in the report is information concerning: (1) the Dutch educational system; (2) objectives, organization, and evaluation (instruments and testing schedules) of the project; (3) the child care workers, with comments on current and future selection and training techniques; (4) the children's daily schedule and the special attention given to problem children; (5) parents' involvement in the program, with special comment on the development of a room in which parents can meet informally with each other and the social worker; and (6) six major limitations on evaluating the project statistically. (ED)