This paper explores the barriers and possible solutions toward the implementation of the goal of a coordinated service system for young children with special needs and their families. The components of the vision of a comprehensive, interagency, multidisciplinary, coordinated service system are outlined, such as interdisciplinary cooperation, a significant family role, and services for all eligible children. A table lists some of the grounding assumptions in the health, special education, and social services professions. The paper discusses whether change called for by Part H of the Individuals with Disabilities Education Act should be revolutionary, which would attack these grounding assumptions, or evolutionary, which would preserve the grounding assumptions. The paper then considers how the actual implementation of the vision would vary by context, how the steps necessary to move from the current system to the new vision must be determined, and how to develop strategies by which appropriate resources are obtained for the new vision. (Contains 36 references.) (JDD)