Understanding LC Call Numbers
Reading LC Call Numbers
To be able to read LC call numbers efficiently is quite a skill. This tutorial was created to help library users uncover the mysteries of LC call number reading. Let's start with a sample call number:
QE534.2.B64
Call numbers can begin with one, two, or three letters.
- The first letter of a call number represents one of the 21 major divisions of the LC System. In the example, the subject "Q" is Science.
- The second letter "E" represents a subdivision of the sciences,
Geology. All books in the
QE's
are primarily about Geology.
- Books in categories E, United States History, and F, Local U.S. History and American History, do not have a second letter (exception: in Canada, FC is used for Canadian history).
- Books about Law, K's, can have three letters, such as KFH, Law of Hawaii. Some areas of history (D) also have three-letter call numbers.
- Most other subject areas will have call numbers beginning with one or
two letters.
- For most of the subject areas, the single letter represents books of a general nature for that subject area (i.e. Q - General Science or D - General World History).
Numbers after letters.
- The first set of numbers in a call number help to define a book's subject.
- "534.2" in the example teaches us more about the book's subject. The range QE 500-625 are books about "Dynamic and Structural Geology."
- Books with call numbers QE534.2 are specifically "Earthquakes, Seismology - General Works - 1970 to Present"
- One of the most frequently used number in call numbers is "1" which is
often used for general periodicals in a given subject area.
- For example, Q1.S3 is the call number for the journal Science.
- Journals are also given call numbers based on the specific subject.
- For example, QE531.E32 is the call number for the journal Earthquake Spectra as QE531 is the call number for periodicals about "Earthquakes, Seismology"
Cutter Number
- The cutter number is a coded representation of the author or organization's name or the title of the work (also known as the "Main Entry" in library-lingo).
- Charles Ammi Cutter first developed cutter numbers using a two-number
table.
- A three-number table was developed in 1969.
- In our above example, QE534.2.B64, the .B64 is taken from the
two-number table and represents the author's last name, Bruce A. Bolt.
- The book is Earthquakes.
- Some books have two Cutters, the first one is usually a further
breakdown of the subject matter.
- For example, QA 76.76 .H94 M88 is a book located in the Mathematics
section of the Q's.
- QA 76 is about Computer Science.
- The ".76" indicates Special Topics in Automation.
- ".H94" tells us that this is a book about HTML.
- "M88" represents the last name of the first author listed's last name, Musciano.
- The book is HTML: The Definitive Guide
- For example, QA 76.76 .H94 M88 is a book located in the Mathematics
section of the Q's.
Shelving and Locating
Items are shelved by call numbers - in both alphabetical and numerical order. The letters at the beginning of the call number are alphabetical. The numbers immediately following are in basic numerical order, i.e. 5 then 6, 50 is after 49 and before 51, and 100 is after 99. Thus,
| QD 1 .A3 |
QD 2 .A31 |
QD 3 .Z4 |
QD 29 .C3 |
QD 30 .A2 |
The cutter numbers (.A3, .A31, .Z4, .C3, and .A2 in the above example) are sorted first by the letter and then by the number as a decimal. For QD 1 .A5 think of it as being QD 1 A 0.5, for QD 1 .A332 read QD 1 A 0.332. Therefore,
| QD 1 .A3 |
QD 1 .A31 |
QD 1 .A311 |
QD 1 .A4 |
QD 1 .A41 |
QD 1 .A415 |
QD 1 .A42 |
Dates, volume and issue numbers, copy numbers, and other annotations are like an additional cutter number but are shelved by basic alphabetization (numbers alone come before letters):
| Q 10 .C3 |
Q 10 .C3 1933 |
Q 10 .C3 1990 |
Q 10 .C3 1996 c.1 |
Q 10 .C3 1996 c.2 |
QD 1 .A5 v.1 |
QD 1 .A5 v.2 |
QD 1 .A5 v.2 Plates |
QD 1 .A5 v.2 Suppl. |
