Noting that the inclusion of young children with disabilities in early childhood programs has important short-term behavioral and social benefits for such children and their families and that arguments for an "ethic of inclusion" have emerged within the field, this paper maintains that much remains to be learned about the nature of early childhood inclusion. The paper notes that potentially important differences between programs involved in research and community-based preschool programs limit the ecological validity of much of the extant research on early childhood inclusion. Ecobehavioral assessment is described as one systematic approach to obtaining specific environmental and behavioral information about children's experiences in community-based early childhood programs. The paper then describes a multi-site, ecobehavioral investigation to assess the nature of preschool children's experiences in inclusive programs. Participating were 112 preschoolers with and without disabilities in 16 community-based, inclusive preschool programs in four states. The study found that children with and without disabilities exhibited similar child behaviors and were meaningfully engaged in a variety of adult-and child-initiated activities within similar activity contexts. Children without disabilities participated in more child-child social behaviors than did children with disabilities and also received less adult support and attention. These findings suggest that additional focused intervention efforts are necessary to promote and support peer interactions and social networks within inclusive preschools. A second study is also described, which examined levels of engagement in children with and without disabilities in adult- and child-initiated activities. That study found that children with and without disabilities had similar levels of engagement, were engaged more often in child- than adult-initiated activities, and were engaged in different types of child behavior when adults and children initiated activities. (Contains 33 references.) (KB)