The fundamental principles guiding the development of the Library of Congress subject headings system are effective responses to user needs and to literary warrant, use of uniform and unique headings, provision of direct access to specific subjects, stability, and consistency.

3.1 User needs

3.2 Literary warrant

3.3 Uniform heading (one heading per subject - control of synonyms)

3.4 Unique heading (one subject per heading - control of homographs)

3.5 Specific and direct entry

3.6 Stability

3.7 Consistency

See also:

Principles of Heading Construction