The document is a user's manual and reference book/primer for Flue Gas Desulfurization Information System (FGDIS) users and recipients of the quarterly Utility FGD Survey. Part I, interactive computer procedures for the FGDIS, addresses the use of and terminology related to the use of the computerized data base. Part II, FGDIS terminology, addresses FGD technology as it relates to this computerized data base. The primary thrust of Part II concerns equipment/component classifications: major equipment items and construction materials are broken down into primary, secondary, and tertiary categories referred to as generic type, specific type, and trade/common name (or common design). This is supported by an appendix that describes the use of problem/solution codes. A glossary, defining common scrubber- and boiler-related FGD terms, includes definitions of data field titles in FGDIS that may be unclear to new FGDIS users or individuals somewhat detached from the system.