Because the Library of Congress classification schedules were developed over a long period of time, few schedules contain the same order of topics and the same wording in captions, each schedule having its own idiosyncrasies. Informal "models" for the development of some of the schedules have existed and been followed for several years. This instruction sheet standardizes the various versions of those models. It also provides other guidance in establishing new class numbers to achieve a consistent arrangement and wording of topics in the schedules.


1. For an orderly arrangement of topics in an individual discipline, provide first for a preliminary section specifying form s of publication and special aspects of the discipline as a whole, then for a logical breakdown of the discipline into subtopics.

2. Do not position subtopics of the discipline in the preliminary section, and do not intersperse preliminary captions among the subtopics, unless it is characteristic of a particular class to locate certain material contrary to these instructions. For example, in some classes provision for place is characteristically located at the end of a section for the discipline after all subtopics.

3. Class works on subtopics in special forms with the subtopic, not with the form at the head of the topic.

4. Adding form captions. Add standard form captions under a topic upon receipt of the first appropriate item but only when one or more standard form captions already exist for the discipline in question or when preparing a major development. Examples of major developments are DK4000+, Poland; TJ807+, Solar energy; and TD1020+, Hazardous substance disposal.

5. Classification models. Insofar as feasible, follow the models on the next several pages, adopting the same order and captions within the specified schedules. The presence of topics on a model list does not mean that all topics must be established for a major development. The most important topics may be selected and other topics added later if needed.

If no model for a class exists, follow precedent within the class for the order and captions.

image\POINT_BL.gif Model for the D Schedule

image\POINT_BL.gif Model for the H Schedule

image\POINT_BL.gif Model for the Q Schedule

image\POINT_BL.gif Model for the R Schedule

See also:

Alternate Class Numbers