This document is the newest revision of the third manual documenting the National Agricultural Library database. Since it began in 1970, the AGRICOLA database has continued to grow and to change steadily; new subfiles have been added, database record formats have been expanded, and subject category code schemes have been modified several times. The number of users of the file has grown steadily as well, and this revision of the manual attempts to meet the needs of both sophisticated searchers and the growing number of end users of information. The basic arrangement remains the same, although several changes in content and emphasis have been made. Section I now contains a general discussion of characteristics of agricultural literature that many affect online retrieval. Section II updates the technical aspects of AGRICOLA, documenting policies and various elements of the database records, e.g., subject codes and language abbreviations. Sections III and IV, which document the database as it is loaded on the DIALOG and BRS (Bibliographic Retrieval Services) systems, concentrate on fields in the database record and assume that the reader has other sources covering the mechanics of searching the two systems. Section V covers database selection and cross-database searching. Summaries of the category codes, DIALOG/BRS basic functions, and DIALOG/BRS retrieval codes are included. (BBM)