Described in this report is a home-based, cognitive-affective intervention program involving 93 mothers and their children. This demonstration program sought to show that the principal cognitive element missing from the experience of low-income children in preparation for schooling is a sufficient amount of concept-building verbal interaction in the family, especially between mother and child. Four successive cohorts, entering in 1968, 1969, 1970, and 1971, in groups ranging from 70 percent to 100 percent black were enrolled in the program. The program consisted of 92 semi-weekly, half-hour home sessions spread over 2 years. These were held by interveners called 'Toy Demonstrators' who were trained to show a mother, by participating in home play sessions with her child, how to interact verbally to enhance the child's conceptual and socioemotional development. Test results (Stanford-Binet and WICS, Peabody Picture Vocabulary Test, Reading and Arithmetic Standard Score on the Wide Range Achievement Test, and Child's Behavior Traits) for the four cohorts of children indicate that the program probably does work, within the context of the research project, with fairly substantial and stable IQ gains of about 17 points. (CS)