The Defender CAU is a semipublic agency which provides legal and social services to nearly 1,500 nondelinquent children annually, including abuse and neglect victims, status offenders, children involved in adoption disputes, and mental health/mental retardation commitments. The context evaluation reviewed the literature of advocacy and children's rights, traced the history and development of the CAU and studied the relationships between the CAU and other Philadelphia agencies. The process evaluation included a study of the unit's organization, particularly its staffing, philosophy, and internal views of effectiveness. Unit operations were examined, including information and client flows, procedures and effectiveness of courtroom work and field activities, and the exigencies of working in the Philadelphia system. The CAU's impact on its clients' school performance, family stability and experiences in the justice and social service system were also studied. The CAU's effectiveness in preventing delinquency was highlighted. Report recommendations include establishing an active advisory council, creating a stronger impression of separateness from the Family Court, and strengthening the child-centered nature of their representation. The CAU should resolve the role ambiguity between representing the child's best interests and being an advocate for the child's stated wishes, adopt a more aggressive courtroom posture, and resolve attorney-social worker conflicts to strengthen intraorganization communications. Tabular data, approximately 60 references, 23 court case citations, and 6 statute citations are included.