Since the foundations of international cataloguing standards were laid in 1971, a host of unforeseen factors have had a dramatic impact on libraries, forcing them to rethink their cataloguing policy.The automated processing of bibliographic data has become commonplace, while new modes of electronic publishing are developed every day. The rise of databases compiled on an international scale raises the problem of how to create codes and systems capable of being used in all countries concerned. Finally, financial pressures have forced many libraries to do more minimal level cataloguing to keep pace with the growth of publishing output.Adopting a user-focused approach, this study systematically defines what information library patrons and staff, publishers, distributors, and retailers expect to find. The wide range of contexts in which data is used -- from purchasing, cataloguing, and interlibrary loan to reference and preservation -- receives careful consideration.The model set forth here will serve as a welcome starting point to those charged with designing cataloguing codes and systems to suit our constantly evolving information environment.