These three papers report preliminary findings of an early intervention collaboration study on developmentally vulnerable infants and their families in Massachusetts and New Hampshire. Subjects, 190 infants with Down syndrome, motor impairment, or developmental delays of unknown etiology, were recruited from 29 community-based early intervention programs. Each child was evaluated at home, then again after 1 year of service, and at the time of the child's third birthday. The research design also calls for evaluating the child at 6 weeks after preschool entry, and at age 5. The study focuses on: first, the measured effects of distinct aspects of the early caregiving environment on child competence; second, tendencies toward stability in the adaptation of families of children with disabilities; and third, the existence of identifiable subgroups of children and families who demonstrate greater degrees of vulnerability or resilience. The second paper, by Marty Wyngaarden Krauss, specifically addresses stability and adaptation concluding that: (1) mothers in the study did not experience atypical amounts of depression or stress; (2) other sources of stress impact families of children with disabilities; (3) an increased risk for parental stress occurs as behavior problems become manifest; and (4) family cohesiveness and the informal support network serve different functions. The third paper, by Penny Hauser-Cram, focuses on outcomes for the subgroups of children with severe cognitive/psychomotor impairment, children with seizure disorders, and children whose mothers demonstrated large increases in their interactive parenting skills. (DB)