Learn how to read a Library of Congress (LC) call number (classification) to find the item on the shelf.
Find a book using its call number
- In the Library of Congress (LC) classification, the call number starts with a letter (or two), followed by numbers. The letter indicates the subject
- Read call numbers line by line (see example below):
- Books are shelved left to right
The call number is also on the book's spine or front cover:
Shelf signs in most libraries show the first part of the call number and the subject areas:
Library of Congress subject areas
| 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, Books on Music |
| N | Fine Arts |
| P | Language and Literature |
| Q | Science |
| R | Medicine |
| S | Agriculture |
| T | Technology |
| U | Military Science |
| V | Naval Science |
| Z | Bibliography, Library Science, Information Resources (general) |
National Library of Medicine (NLM) subject areas
Preclinical Sciences
| QS | Human Anatomy |
| QT | Physiology |
| QU | Biochemistry. Cell Biology and Genetics |
| QV | Pharmacology |
| QW | Microbiology and Immunology |
| QX | Parasitology |
| QY | Clinical Laboratory Pathology |
| QZ | Pathology |
Medicine and Related Subjects
| W | General Medicine. Health Professions |
| WA | Public Health |
| WB | Practice of Medicine |
| WC | Communicable Diseases |
| WD | Disorders of Systemic, Metabolic or Environmental Origin, etc. |
| WE | Musculoskeletal System |
| WF | Respiratory System |
| WG | Cardiovascular System |
| WH | Hemic and Lymphatic Systems |
| WI | Digestive System |
| WJ | Urogenital System |
| WK | Endocrine System |
| WL | Nervous System |
| WM | Psychiatry |
| WN | Radiology. Diagnostic Imaging |
| WO | Surgery |
| WP | Gynecology |
| WQ | Obstetrics |
| WR | Dermatology |
| WS | Pediatrics |
| WT | Geriatrics. Chronic Disease |
| WU | Dentistry. Oral Surgery |
| WV | Otolaryngology |
| WW | Ophthalmology |
| WX | Hospitals and Other Health Facilities |
| WY | Nursing |
| WZ | History of Medicine. Medical Miscellany |
| 19th Century Schedule |
Dewey Decimal System subject areas
| 000 | Computer Science, Information, & General Works |
| 100 | Philosophy & Psychology |
| 200 | Religion |
| 300 | Social Sciences |
| 400 | Language |
| 500 | Science |
| 600 | Technology |
| 700 | Arts & Recreation |
| 800 | Literature |
| 900 | History & Geography |