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Tarleton State University Libraries Unit 5
LC CLASSIFICATION & CALL NUMBERS
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image of numbers   Each item in the libraries' collections has a unique call number, which tells where the item is located on the shelves. Tarleton libraries use Library of Congress (LC) Classification, which arranges items by broad/general subjects, then by sub-subjects so subject-related items are shelved together and more easily located.

Library materials are shelved alphabetically and numerically depending on their call numbers, which are determined by the items' subjects. Also, call numbers have been assigned to many well-known authors so their works are shelved together. Knowing the classification letter(s) for your subject area can help you locate materials on specific and related subjects, as well as browse the shelves for "fortunate finds."

For an overview of the Library of Congress classification system, see the Library of Congress Classification outline, which shows the letters and titles of main classification classes and is offered online by the Library of Congress Cataloging Policy and Support Office.


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FORMATS USED TO WRITE CALL NUMBERS
Call numbers on library materials and in the catalog appear in two formats and are read from top to bottom or left to right, as shown below:


Stacked on the spines of materials
""Z
""678.9
"".H9
""1987

In a single line
in the libraries' catalog


Z678.9.H9 1987

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HOW TO READ CALL NUMBERS
When reading call numbers, consider each segment before moving on to the next segment. This process is illustrated in the following tables, which explain and give examples of the segments in Library of Congress call numbers. In each row, call numbers are arranged in correct shelf order to show how they would be arranged on library shelves. Bold type indicates the portion of the call number being discussed.

Letter(s) comprise the first segment and indicate an item's subject and sub-subject.
The library's arrangement is based on these letters, so it's primarily alphabetic.
H
41
.E561
HA
17
.K4
1971
HB
34
.N6
1990
HC
240
.C518
2000
 
Numbers comprise the next segment and more specifically indicate subject.
Read these numbers as whole numbers. If this component contains a period and another number (i.e. 674.7 and 678.93), read it like you would a whole number with a decimal.
Z
665
.M672
1984
Z
674
.K35
Z
674.7
.L52
1990

Z
678.93
.M53
A54
1987
 
Letters and numbers comprise the next segment and indicate an author's last name or a subject subdivision.

Read the letters alphabetically.


Read the numbers after the letter as decimals.

KF
387
.C53

M3.1
.M466

KF
387
.H36

M3.1
.M5

KF
387
.K55

M3.1
.M84

KF
387
.L37
M3.1
.M9
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Another segment of letters and numbers may follow the previous one.
Again, read the letters alphabetically and the numbers as decimals.
 
The last segment, if given, indicates the item's publication date.

Items with the same call number are shelved chronologically by publication date.
PS
3515
.U274
A6
1959
PS
3515
.U274
A6
1969
PS
3515
.U274
A6
1971
PS
3515
.U274
A6
2000

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