This report describes library applications of electronic bulletin board systems (BBS), i.e., telecommunications software designed to receive incoming calls from other computer systems. It begins by explaining the basics of a BBS; describing a typical configuration, i.e., a microcomputer and a modem connected to standard phone line bulletin board software; and providing a step-by-step example of an exchange of information using a BBS. The advantages of sending information via a BBS rather than over telefacsimile are then discussed, together with the differences between a BBS and an electronic mail system. Special features of the BBS are described, including public announcements stored in text files, help screens, expert and novice modes, security features, conferences, and message threading. The advantages of a multitasking program are discussed, and useful applications of a BBS in a library are suggested, including interlibrary loans, answering reference questions, and providing public bulletin boards to announce library activities or to attract professionals to the library with current information about microcomputers. Specific instructions for setting up a BBS are followed by some advice on making use of the system once it is set up. Annotated listings of BBS software programs, microcomputer-based electronic mail programs, and programs that create interlibrary loan requests for transmission are included, as well as a glossary of terms and a list of suggested readings. (SD)