SIMBAD (Set of Identifications, Measurements, and Bibliography for Astronomical Data) is produced and maintained by the Centre de Données Astronomiques de Strasbourg (CDS). Access to SIMBAD requires a password, and application may be made by e-mail to question@simbad.u-strasbg.fr or SIMBAD::QUESTION. SIMBAD may be accessed in the United States via the Smithsonian Astrophysical Observatory (SAO), where a gateway to SIMBAD is maintained under contract with NASA. U.S. astronomers should apply directly to SAO for access, by e-mail to SIMBAD@cfa.harvard.edu. SIMBAD charges for its services, but these costs are supported by NASA for astronomers at institutions in the United States. SIMBAD is accessible via telnet to simbad.u-strasbg.fr (130.79.128.4) on the Internet or via SET HOST SIMBAD (29588). As of March 1994 it contained 1,030,000 objects. For stars (over 665,000 entries) the data include coordinates, spectral type, blue and visual magnitudes, and proper motions. The data for galaxies and quasars (some 80,000 entries) and other non-stellar objects (about 250,000 entries) include coordinates, blue and visual integrated magnitudes, morphological type, size and position angle. In addition there are observational data for some 20 different types of measurements. Over 1,000,000 citations of objects are provided, based on 76,000 bibliographic references complete back to 1950 for stars and to 1983 for non-stellar objects. The total number of identifiers (including those for the PPM star catalog) is 3,300,000. Stars from the Guide Star Catalog can be extracted for any sky region within SIMBAD using the findgsc command. As with NED, batch jobs for retrieval of many objects at a time are supported. [References: Egret, Wenger and Dubois (1991), Egret (1992), SIMBAD III (1992).]