A child's behavior is caused by many factors. Some are "inside" the child, such as neurons and glands, memories and motivations. "Outside" the child are factors such as his parents, his siblings, his family's socioeconomic status, his house, his school, the hue of his skin, television, and many others. The major theoretical systems in pediatrics and child psychiatry have always been concerned with the influence of both the internal and the external factors upon the development of the child. Particular emphasis has been put, in theory, on the importance of the family and the way the child, an organism with biologic and psychologic needs, negotiates those needs within the nurturing and socializing unit called the family. The techniques of intervention which have been developed by pediatricians and child psychiatrists have been aimed almost entirely at the child as a separate organism. Though the theories have taken account of the importance of the family in the child's development and behavior, the techniques used to help the child have not. Pediatricians acknowledge the significance of the family in the management of a child's illness, yet traditionally they examine the child but talk with the parents, mostly the mother. A team of pediatricians and child psychiatrists at the Philadelphia Child Guidance Clinic and the Children's Hospital of Philadelphia have joined to explore the influence of the family in the development of psychosomatic and psychogenic symptoms in children and in the management of pediatric illness. Their researches in psychosomatic syndromes, supported by an NIMH grant (#21336-02), have been described in the bibliography at the end of the third article. The three papers which follow illustrate how includ ing the family in the field of observation leads to a richer way of understanding and treating children's illnesses. —Salvador Minuchin, M.D.