1946 to 1969. His analyses shaped the subsequent cataloging rules. The published American and Anglo-American cataloging rules in the 20th century were: Anglo-American rules: American Library Association rules: Library of Congress rules: AACR: AACR2: AACR2-R: The 21st century brought renewed thinking about library cataloging, in great part based on the increase in the number of digital formats, but also because of a new consciousness of the nature of the "Work" in the bibliographic context, often attributed to the principles developed by Lubetzky. This was also supported by the work of the International Federation of Library Associations and Institutions on the Functional Requirements for Bibliographic Records (FRBR), which emphasized the role of the work in the bibliographic context. FRBR created a tiered view of the bibliographic entity from Item, Manifestation, Expression, to Work. Item refers to the physical form of the book. Manifestation refers to the publication. Expression meaning the translation of the book from other languages. Work refers to the content and ideas of the book. This view was incorporated into the cataloging rules subsequent to AACR2-R, known as Resource Description and Access (RDA). England The Bodleian Library at Oxford University developed its cataloging code in 1674. The code emphasized authorship, and books by the same author were listed together in the catalog. We can trace the origins of modern library cataloging practice back to the 1830s and Anthony Panizzi's 91 rules. Panizzi's singular insight was that a large catalog needed consistency in its entries if it was to serve the user. The first major English-language cataloging code was that developed by Sir Anthony Panizzi for the British Museum catalog. Panizzi's 91 rules were approved by the British Museum in 1839, and published in 1841. The British Museum rules were revised up until 1936. The library departments of the British Museum became part of the new British Library in 1973. Germany and Prussia The Prussian government set standard rules called (PI) (Prussian Instructions) for all of its libraries in 1899. These rules were based on the earlier of the University Library at Breslau by Karl Franz Otto Dziatzko. The Prussian Instructions were a standardized system of cataloging rules. Titles in literature are arranged grammatically not mechanically and literature is entered under its title. These were adopted throughout Germany, Prussia and Austria. After the adoption of the Paris Principles (PP) in 1961, Germany developed the (RAK) in 1976/1977. The goal of