The Fort Detrick Information Retrieval System is a system of computer programs written in COBOL for a CDC 3150 to store and retrieve information about the scientific and technical reports and documents of the Fort Detrick Technical Library. The documents and reports have been abstracted and indexed. This abstract, the subject matter descriptors, the document's title, the personal authors, the corporate authors, the document's series and contract numbers, any security classifications, and other pertinent information make up the master record of the information retrieval system. The size of this record is up to 2300 characters, 980 of which are allotted to the abstract and 240 for up to 48 5-digit numeric descriptor codes to indicate the document's subject matter. A search or inverted file is used in a subject matter search of the master file. In addition to Boolean search capability, provision has been made for printing six book catalogs, e.g., personal author, corporate author, contracts, descriptors, etc. while the records of the master file are arranged by accession number of the individual document and the subject matter of that document is indicated by one or more descriptors codes. The inverted file records are arranged by descriptor. (Author/NH)