This document is the second part in a report on longitudinal evaluations of preschool programs. Part I reviewed long-term, controlled studies in order to generally assess the impact of preschool intervention. Part II reviews follow-up data in order to resolve the following five questions: (1) Do children in experimental programs continue to gain in intellectual development as long as intervention continues?, (2) Are gains increased or maintained after termination of the programs?, (3) Is development enhanced by beginning intervention at earlier ages, including the first years of life?, (4) What kinds of programs are most effective for long-range impact?, and (5) Which children from what circumstances are most likely to benefit in the long run from early intervention? The report includes discussion of the nature and limitations of the data used, methodological problems, effects of preschool intervention in group settings, effects of home-based intervention, a sequential strategy for early intervention, and the ecology of intervention, in which focus is on the characteristics and problems of disadvantaged families. (DP)