This report does not provide a thorough analysis of the quality (validity and reliability) of parole data, but rather serves as a general guide to the collection and maintenance of parole data in Illinois, as well as a listing of the data avilable, for which years, where the data are kept, and how to obtain access to them. Following an overview of the adult parole data, the data controlled by the Prisoner Review Board, which was the Parole and Pardon Board before the enactment of the Illinois determinate sentencing law, make parole and release decisions and maintains records for these decisions. Data the Board collects and generates are considered. The discussion of data the Board generates deals with decision files, the decisionmaking worksheet, standard report, and uniform parole reports. Several sections of the report focus on data collected and maintained by the Department of Corrections. These records relate to parole or release supervision. The presentation is organized according to the form in which the data exist, i.e., manual, microfilm, and computer files. Since some Illinois parolees are paroled from Federal institutions, Illinois data in the Federal parole system are reviewed. Examples of various forms and materials used in the parole and release data system are appended. An annotated bibliography of 111 entries is provided, along with a glossary and an index to sources. Some tabular data are provided.