"The Energy Data Base: Subject Thesaurus contains the standard vocabulary of indexing terms (descriptors) developed and structured by the technical staff of the Office of Science and Technical Information as part of its subject indexing activities for the building and maintenance of energy information data bases for the Department of Energy. This structured vocabulary reflects the scope of DOE's research, development, and technological programs and encompasses terminology derived not only from the basic sciences but also from the areas of energy resources, conservation, safety, environmental impact, and regulation. The terminology of this thesaurus controls the subject searching of the Energy Data Base (EDB) available on the DOE on-line retrieval systems. The terminology is also used for the subject control of other OSTI data bases available only on DOE/RECON. Descriptors are added to the thesaurus on the basis of need, i.e., when a document contains a concept for which there is no adequate term or terms in the thesaurus. (...) There are over 25,000 entries."