AACR -  L C Descriptive Rules - british museum cataloguing rules:

Anglo-American cataloging rules / prepared by the American Library Association, the Library of Congress, the Library Association, and the Canadian Library Association. - North American ext.- Chicago : American library Association, 1967. - Reprinted in 1970 with supplement of additions and changes. - British text published : London Library Association, 1967. 

At this time, the long cherished goal of international code renewed itself and appeared a possibility. The International Conference on Cataloguing Principles convened in Paris in October 1961, adopted and accepted a statement of principles in whole or part by delegations from 53 countries and 12 international organisations. The Report of the International Conference was issued in 1963. It drew upon Lubetzky's 1960 code and restated the objectives of both Lubetzky and Cutter. The statement of principles rested on the objectives and were expressed in specific terms. The importance of this report lies in its endorsement of corporate entry and establishment of natural rather than grammatical order of arrangement of title, thus, removing the major differences between the Anglo-American and Germanic traditions of cataloguing. Following the International Conference on Cataloguing Principles many other national catalogue codes were revised or developed, eg, the German Code (Regeln fur die alphebetische katalogisierung, the Swedish code, the Danish code, etc.), leveling the differences between national practices. The new code (known as AACR 1) appeared in 1967 and was received by the profession with, a mixed reaction. The rules in the code were organised in 2 parts, part 1 dealing with entry and 'heading consisting of four chapters, and part 2 covering description presented in 10 chapters. 

The code applied reevaluation of the existing practices. It was seen as a better code in terms of its more logical grouping of the rules with emphasis on conditions of authorship rather than on classes of authors (married women, princes of blood, etc) and kinds of publications (anna, dictionaries, encyclopaedias, etc). It corresponded, more than the earlier codes to the patterns of intelligent users instead of blindly ruling preparation of entries, which may be precise, consistent and technically correct. It gave preference to the form of name preferred or used by the author than his real/official name. Title page of the item catalogued was prescribed as the source of information for cataloguing against the old practice of deriving details from outside sources. Similarly, in the case of change of names of corporate bodies, entry was required under the changed/new name. The code, further emphasised the functionof assembling bibliographic units by providing uniform title entry more widely. But some of the vestiges of old practices remained. For example, the authorial-status to editors and compilers, entry under place names for certain corporate bodies continued. On this and certain other points since the American and British Committees could not reach agreement, the code was published in two slightly differing texts like the 1908 code. 

When work on AACR 1 began, books and periodicals were the basic and popular materials. Card catalogue was the norm. But when the code appeared in 1967 the situation changed vastly. As a result of technology, a variety of new media (non-book materials) found their way into libraries. Computer manipulation of data made possible other forms of catalogue. The need to integrate the descriptive records (catalogue entries) of different forms of material (book and non-book items) necessitated studies to find analogies between their characteristics). IFLA brought out a document entitled International Standard Bibliographic Description (for single and multi-volume monographic publications) in 1971. This was later improved/revised and published in 1974 as ISBD(M): International Standard Bibliographic Description for Monographic Publications, 1st standard ed. Along with it another standard for serials, viz., ISBD(S) International Standard Bibliographic Description for Serials was also published. The AACR I incorporated these documents and revised chapter 6 (separately published monographs) in 1974 followed by chapter 12 (for audio-visual media and special instructional materials) in 1975 and chapter 14 (for sound recordings) in 1976. IFLA's International standards for other kinds of material including a general one followed in succession. 

This piecemeal revision was found unsatisfactory. It needed development of overall principles and integration of descriptive rules for various media. The expanded cooperation between the cataloguing agencies in Great Britain, America and other countries as well as the increase in the use of UKMARC and LCMARC brought about agreement for a single unified text of code, the ambiguities and differences resolved.'