Presents the only comprehensive treatise on the Library of Congress Subject Headings (LCSH) system, now fully updated to address LCSH in the electronic environment. This book is the only comprehensive treatise on the Library of Congress Subject Headings (LCSH) system. It offers users a complete and definitive guide to a challenging area of study. Chan presents a brief history of the system, analyzes its principles, and describes its vocabulary and subject authority control. She then discusses the application of LC subject headings to LC MARC records and outlines the Library of Congress's policies on the assignment of subject headings in general and the treatment of certain types of materials in particular. This new edition updates the text according to policies governing current practices in using LCSH, and the highlighted relevance of LCSH in the global electronic environment. Part 3, completely rewritten, includes a chapter on FAST (Faceted Application of Subject Terminology), which is an LCSH-based controlled vocabulary for electronic resources.