This report traces the history of the national reporting system for mental health statistics which started with the United States census of 1840, when the first attempt was made to enumerate "insane and idiotic" persons in the population. Section 1 traces the national reporting program on patients in mental institutions under auspices of the Bureau of the Census from 1840 until 1946. Section 2 describes the national reporting of patients in mental institutions from 1947 to 1981. Section 3 provides a summary and concluding remarks about the changes and expansion within the mental health care delivery system that have occurred over the years. Tables are included which detail the types of information gathered in the 1840-1846 censuses (e.g, agency responsible, initial and final survey years, coverage, and scope of information); the inventories of mental health facilities,1967-1981; and the client sample survey program, 1969-1981. The appendices, which make up the greater part of the report, include samples of the schedules and inventories used in the censuses, the mental health facility inventory forms, and a listing of mental health statistical notes and service system reports and other publications of the National Institute of Mental Health, Division of Biometry and Epidemiology. (LLL)