The Cambridge Crystallographic Data Centre is concerned with the retrieval, evaluation, synthesis, and dissemination of structural data based on diffraction methods. The source of input is almost entirely primary journals. Bibliographic information and numeric data on crystal and molecular structures are on magnetic tapes. The bibliographic file is ordered in 86 chemical classes, and by molecular formula within each class. The numeric file contains data corresponding to each entry in the bibliographic file published since January 1960. This paper discusses the Centre's publications and services including: (1) bibliographic magnetic tape service, (2) hard-copy alerting service, (3) retrospective searches, (4) manual searches, (5) numeric data magnetic tape service, and (6) computer programs. A list of the 86 chemical classes used for file ordering, information on the Protein Data Bank, and a breakdown of service charges are appended. (Author/SJ)