The Library of Congress Classification (LCC) is a classification system that was originally developed to organize and arrange the wide-ranging book collections of the Library of Congress. The system divides all knowledge into 21 basic classes, each identified by a single letter of the alphabet and then further subdivided.
The NLM Classification is a system of mixed notation patterned after the LCC where alphabetical letters denote broad subject categories and are further subdivided by numbers. The NLM Classification specifically covers the field of medicine and related sciences.
The table below shows the broad classes for both the LCC and the NLM Classification.
| Class | Library of Congress Classification (LCC) | National Library of Medicine (NLM) Classification |
|---|---|---|
| A | General Works | |
| B | Philosophy, Psychology, Religion | |
| C | Auxiliary Sciences of History | |
| D | World History and History of Europe, Asia, Africa, Australia, New Zealand, etc. | |
| E | History of the Americas | |
| F | History of the Americas | |
| G | Geography, Anthropology, Recreation | |
| H | Social Sciences | |
| J | Political Science | |
| K | Law | |
| L | Education | |
| M | Music and Books on Music | |
| N | Fine Arts | |
| P | Language and Literature | |
| Q | Science | Preclinical Sciences (QS-QZ only) |
| R | Medicine | |
| S | Agriculture | |
| T | Technology | |
| U | Military Science | |
| V | Naval Science | |
| W | Medicine and Related Subjects | |
| Z | Bibliography, Library Science, Information Resources (General) |
Note that the NLM Classification uses schedules QS–QZ and W–WZ which are permanently excluded from the LCC Schedules. This was designed so that the NLM Classification can complement existing LCC within libraries. Keep in mind, however, there are special cases of overlap, and we will discuss those later in this course.