The Survey of Inmates of State Correctional Facilities, also called NPS-25, is a nationwide study of prisoners and prisoner experiences. It is designed to collect information from almost 12,000 inmates housed in State prisons and other adult correctional facilities. The survey is intended to provide basic data on such general inmate characteristics as sex, race, age, education, offense for which imprisoned, and time served in prison, as well as information on the use of drugs and alcohol, income before prison, veterans' status, and inmate programs and activities. Survey information is intended to help State and Federal governments make decisions about State correctional institutions. Further, it will assist researchers in their work related to State prisoners. This manual provides detailed instructions for the performance of the following duties of the interviewer: (1) arranging dates and times to conduct the survey at each assigned facility, (2) drawing a sample of inmates for interview, (3) interviewing all sampled inmates, and (4) conducting records checks for selected information. A glossary of terms is provided.