Library of Congress System

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Library of Congress System

Getting to Know the Library of Congress Classification System

The New York College of Health Professions

Library uses the Library of Congress Classification System for determining its call numbers. Call numbers tell you where an item will be located. They are assigned based on the subject of the book. Materials of a similar subject are grouped together. Physical placement of a call number will vary by item, but generally speaking, books will have their call numbers located on the spine:


The books above are shelved in the correct order. Notice that books are shelved alphabetically by the first letter in the call number.



These books are also in correct order. Notice that within a single letter, or classification, such as “H”, alphabetical order is still used. “HA” comes before “HD”, which comes before “HL”, etc.



In this example, three of the books are within the classification “HA”.

When books have the same first line in a call number, they are shelved in numerical order

If the first two lines of a call number are the same, books are shelved by the third line of the call number, which is a decimal arrangement. A decimal arrangement is shelved number by number. Remember that all .A6 numbers (whether .A6, .A65 or .A652 will come before .A7 numbers, as in the call numbers above. Many call numbers will end with the date of publication.

Call numbers beginning with “REF” are reference books.
These books are kept separate from the circulation collection because they are for in-library use only.
Still have questions?
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