LIBRARY OF CONGRESS CLASSIFICATION.
The library of congress classification system was first developed in the late nineteenth and early twentieth centuries to organize and arrange the book collections of the library of congress. The system was adopted for use by other libraries especially large academic
libraries in the United States. It is still one of the most widely used library classification systems in the world.
The system divides all knowledge into twenty – one basic classes, each identified by a single letter of the alphabet. Most of those alphabetical classes are further divided into more specific subclasses, identified by two-letter or three – letter combinations. For
example, class N (AH) has subclasses NA, architecture; NB, sculpture; ND, painting; among other several subclasses.
Each subclass includes a loosely hierarchical arrangement of the topics related to the subclass, going from general to more specificity. Individual topics are often broken down to specific places, time periods or bibliographic forms. Each topic, also referred to as a
caption, is assigned a single number or a span of numbers. Whole numbers used in this classification may range from one to four digits in length and can be further extended by the use of decimal numbers.
Some subtopics appear in alphabetical rather than hierarchical, lists and are represented by decimal numbers that combine a letter with a numeral such as c 85 or J901. Relationships among topics in the library of congress classification are now shown by the
numbers assigned to them but by indenting subtopics under the larger topics that they are a part of. This makes it different from other more strict hierarchical classification systems such as the Dewey decimal classification where hierarchical relationships among
topics are shown by numbers that can be continuously subdivided.
The following are the basic classes of the library of congress classification system.
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 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
R – Medicine
S – Agriculture
T – Technology
U – Military Science
V – Naval Science
Z – Bibliography. Library science. Information resources (General)