The trusty system presented a unique form of structural adaptation to prison needs that began in many southern States during Reconstruction and was not abolished until the early 1970's. The data for this study were gathered from personal observations of the Mississippi State Penitentiary known as Parchman over a 10-year period, interviews with inmates, and a survey conducted in 1971 of representative inmate groups. An overview of the trusty system considers its benefits; accusations of brutality; and development in Louisiana, Arkansas, and Texas. The history of Mississippi's penal system focuses on Parchman, a penal plantation of over 21,000 acres established in 1900 which remains the only prison for adult male and female felons in the State. Parchman's physical setting, administration, and inmate organization are described in detail. The historical emergence of the penal plantation and the trusty system are attributed to the South's slave society and economic conditions following the Civil War. The discussion of the process used to select trusties compares formal classification systems based on offense, age, marital status, and occupation with the 'folk wisdom' that experienced prison employees develop about characteristics and probable future behavior of inmates. Analysis of data collected on Parchman's trusties indicates that selection was not made on any objective basis but depended on the opinions of the camp sergeants, civilians whose responsibilities were similar to those of the overseers on the slave plantations. The effects of the trusty rank on a prisoner's relations with other inmates and the staff are examined, as is role conflict experienced by the trusties. The Parchman trusties showed a remarkable degree of identification with the staff, and high ranking inmates. The implications of the study's findings for contemporary treatment programs in correctional facilities are discussed. The final chapter describes the prison reforms undertaken by Mississippi since 1972 when a Federal court ruled that conditions in the State penitentiary were unconstitutional. Tables, footnotes, and approximately 100 references are provided.