Spanning the years 1946-1969, this collection contains reports and studies issued by or for the Los Angeles County Probation Department. The reports include annual reports and research reports on specific themes. This collection is especially valuable to researchers concerned with juvenile delinquency and the County's treatment of this social problem.

Some reports bear the stamp of the Catholic Welfare Library, one report that of the Welfare Planning Council, and one of Anne Ostomel, indicating their provenance before arrival at the CSWA.