The Library of Congress Subject Headings (LCSH) is perhaps the most widely adopted subject indexing language in the world, has been translated into many languages, and is used around the world by libraries large and small. LCSH has been actively maintained since 1898 to catalog materials held at the Library of Congress. Proposals for additions and changes are reviewed regularly at staff meetings in the Policy and Standards Division (PSD) and an approved list is published.
The BISAC Subject Headings List, also known as the BISAC Subject Codes List, is a standard used by many companies throughout the supply chain to categorize books based on topical content. The Subject Heading applied to a book can determine where the work is shelved in a brick and mortar store or the genre(s) under which it can be searched for in an internal database.
Classify is an OCLC research prototype designed to support the assignment of classification numbers and subject headings for books, DVDs, CDs, and other types of library materials.