RESUMO
The adoption of the MARC II format for the communication of bibliographic information by the three National Libraries of the U.S.A. makes it possible for those libraries to converge on the remaining necessary common standards for machine-readable cataloging. THREE LEVELS OF STANDARDS ARE IDENTIFIED: fundamental, the character set; intermediate, MARC II; and detailed, the codes for identifying data elements. The convergence on these standards implies that the National Libraries can create and operate a Joint Bibliographic Data Bank requiring standard book numbers and universal serial numbers for identifying monographs and serials and that the system will thoroughly process contributed catalog entries before adding them to the Data Bank. There is reason to hope that the use of the MARC II format will facilitate catalogers' decision processes.