Illinois' enactment of the first juvenile court law in the United States was the culmination of a series of efforts by a number of social work professionals, lawyers, and other humanitarians. When the juvenile court was first established, there was more emphasis on community-based treatment of juvenile offenders and less interest in sending them to institutions. In the early 1900's, widespread support for the new juvenile court system led to the creation of many other juvenile courts modeled after the original court in Chicago. One of the first surveys of the effectiveness of the juvenile court system was completed in 1927. This investigation of Pennsylvania's juvenile court system found many juveniles languishing in detention homes and county jails despite State laws that specifically prohibited the imprisonment of juveniles. Over the years, the intended functioning of the juvenile courts has been impeded by the lack of suitable facilities for the placement of juveniles, the heavy burden placed on juvenile court judges, the lack of a uniform policy among juvenile courts, and the lack of financial support for hiring and in-service training of caseworkers and probation personnel. A review of the early development of juvenile probation focuses on volunteers in probation and the emergence of the professional probation worker. Two sections of the chapter discuss the links between child guidance clinics and the juvenile courts as well as the relationship between juvenile probation and the juvenile courts. The chapter concludes that although progress in improving the juvenile courts has been slow, there have been major achievements, such that current juvenile courts in many jurisdictions are efficient, equitable, and humanistic. Recent developments include the continued strengthening of due process safeguards, accelerated case processing and reduced delays in scheduling trial dates, and a greater reliance on alternative sentencing options. Discussion questions, 4 notes, and 36 references