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How to Read Call Numbers in Engineering: Home

Kresge Engineering Library closed until 2025

The Kresge Engineering Library is temporarily closed due to the Bechtel Engineering Center renovation. We plan to re-open in 2025 when the new Engineering Student Center opens its doors.

Read about the closure here.

Questions? Send us a message and one of our engineering librarians will reach out. 

The Library of Congress Classification System

Books and journals are arranged on our shelves according to the Library of Congress (LC) classification system. Using this system, each book or journal is assigned an alphanumeric call number based on its subject focus. This call number uniquely identifies the item and places it on our shelves near other material on the same subject.

Each call number consists of several parts. For example, consider the call number: 

The FIRST line, TK, defines the class and subclass. These letters specify a broad subject area. Within Class T for technology, TK represents the subclass electrical engineering.

The SECOND line, 7881.6, is the classification number. It should be read as a whole number with a decimal component to determine its location on the shelf. In combination with the class and subclass, the classification number defines the subject matter more finely. In this example, TK7881.6represents magnetic recording (a subdivision of TK— electrical engineering).

The THIRD line, M29, is called a "Cutter Number." This letter-number combination usually indicates author, but it may also represent other information such as further subject subdivision or geographic area. The Cutter number is always present in a call number and may sometimes be a "double Cutter" (TK7881.6 M29 D45 1992 has a double Cutter). The numeric component of the Cutter number is ALWAYS interpreted as a decimal number when determining shelf location. Therefore, the numeric component of M29 should be read as ".29" (and the call number TK7881.6 M29 1993 should file BEFORE TK7881.6 M4 1993).

The YEAR of publication, 1993, may also be present. Not all call numbers will include the year of publication, but most recent books will. These file in chronological order and often distinguish among varying editions of a text.

Other miscellaneous descriptors may be part of the call number. If present, these will usually differentiate the components of a work that has one title but was published as separate volumes or in parts over time.

In using a call number to locate a book on the shelf, consider each component of the call number in turn before moving on to the next segment.

As an example, the following call numbers are arranged in the order they should appear on the shelves:

QA            QA            QA            T            T            T            TA            TK            TK            TK            TK
76             76              76             3            39          39           3              7881         7881.15    7881.15     7881.6
F75           F75            F8             Z37        W45       W45        Z3            L444         D2            D2            M29
v.1             v.2             v.1                          M226      M26                       1994         1988         1995         1993
                                                                1989      1989                        v.2

Use the major classification headings in the next section as a basic guide to browse shelves in the Engineering Library.

To find specific subjects, search UC Library Search using Keywords as your search type. Then, identify the call numbers for relevant books from your search and browse for other books near these call numbers.

If you have difficulty locating items on the shelves or have other questions about call numbers, please ask at the Engineering Circulation Desk.

Major Classification Headings Used in the Engineering Library

From the Library of Congress Classification Outline

GB Physical geography.
 651 - 2998Hydrology. Water.
GC Oceanography.
 1000 - 1581Marine resources. Marine pollution.
Q Science (General).
 180Operations research.
 300 - 390Artificial intelligence. Information theory.
QA Mathematics.
 75 - 76Computer science.
 801 - 939Analytic mechanics. Fluid mechanics.
QC Physics.
QD Chemistry.
QE Geology.
R Medicine.
 856 - 857Biomedical engineering. Electronics. Instrumentation.
 895 - 920Medical physics. Medical radiology. Nuclear medicine.
T Technology.
 55.4 - 60.8Industrial Engineering.
 385Computer graphics.
TA Engineering (General). Civil Engineering.
 349 - 359Mechanics of engineering. Applied mechanics.
 401 - 492Materials of engineering and construction.
 630 - 820Structural engineering. Geotechnical engineering.
 1501 - 1820Applied optics.
TC Hydraulic engineering.
TD Environmental engineering.
TE Highway Engineering. Roads and pavements.*
TF Railroad engineering and operations.*
TG Bridge engineering.*
TH Building construction.
TJ Mechanical engineering and machinery.
 163Power resources. Energy conservation.
 210.2 - 225Robotics. Control engineering.
TK Electrical engineering. Electronics. Nuclear engineering.
 5101 - 6720Telecommunications.
 7800 - 8360Electronics.
 9001 - 9401Nuclear engineering.
TL Motor vehicles. Aeronautics. Astronautics.
TN Mining engineering. Metallurgy.
TP Chemical technology.
TS Manufacturing.
 155 - 194Production management. Operations management.
VM Naval architecture. Shipbuilding. Marine engineering.


Most campus material in this classification is shelved in the Transportation Studies Library at 412 McLaughlin Hall.