[영문]The concept of resilience provides a necessary framework for understanding the varied ways in which some children do well in the face of adversity. The debate on resilience in children has shifted from an emphasis on factors to an emphasis on processes and mechanisms and from identifying resilience to promoting resilience. Children in long-term foster-care have experienced a range of early adversities which continue to affect their self-esteem, self-efficacy and capacity to cope with developmental challenges. Risk and protective characteristics in the foster-child, the foster-carers, the birth family and the agencies involved with the child will interact in complex ways to produce upward or downward spirals. This article reports on a longitudinal study of children in long-term foster-care, funded by the Nuffield Foundation. It provides a psychosocial model that links inner and outer worlds, developmental theory and social work practice, to explore why some children appear to be making good progress while others continue to experience multiple developmental difficulties.