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The University of Massachusetts Amherst
Libraries Ask Us

Creating More Powerful Searches

Metadata is a powerful tool

Starting with classification

Most print resources in the UMass Amherst Libraries are organized by Library of Congress call numbers. You'll also hear these referred to as "LC numbers." LC numbers allow us to group resources together by subject.

There are 21 main LC call number classifications:

A: General Works M: Music & Books on Music
B: Philosophy, Psychology & Religion N: Fine Arts
C: Auxiliary Sciences of History P: Language & Literature
D: World History & History of Europe, Asia, Africa, Australia, New Zealand, etc. Q: Science
E: History of the Americas R: Medicine
F: History of the Americas S: Agriculture
G: Geography, Anthropology & Recreation T: Technology
H: Social Sciences U: Military Science
J: Political Science V: Naval Science
K: Law Z: Bibliography, Library Science, Information Resources
L: Education

It's like a street address!

As you browse an aisle of books, it's kind of like walking down a street of similar houses. Each book within a range of numbers may have a different cover and author, but you'll notice that books sitting next to each other on the shelf will cover similar or related topics.

Let's look at an example call number, to see how to read it:

NA642 .M67 2004

NA Letters: The first letter of an LC call number denotes the general classification. Here, our example is under N, which is Fine Arts. If there is a second (or rarely a third) letter, it tells you the sub-classification. NA is for Architecture. Letters are arranged alphabetically. Therefore, NA comes before ND, which comes before NK and so on.
642 Numbers following the letters: These are the subject of the book. 642 is History of Modern Architecture, specifically the 19th and 20th centuries. These are read as whole numbers, which means that 642 comes before 643.
.A733 Cutter number: The Cutter number is what indicates the author or title of a book. We use a table to match a name or title with a set of numbers. .A733 represents a title beginning with the word "Architectures." The letter part of this number is shelved alphabetically, and the number is read as a decimal.
2004 Year: Year of publication

Just so you might see how a call number is related to the book itself, this call number is for a book called Architectures: Modernism and After, edited by Andrew Ballantyne. The subjects for this book are Architecture, Modern -- 19th century and Architecture, Modern -- 20th century.

Some call numbers can be longer and have two sets of Cutter numbers. Let's use this example:

HN49.D3 P74 2005

HN Letters: This example is for the general classification of Social Sciences and sub-classified under Social History & Conditions / Social problems / Social Reform.
49 Numbers: The subject area for special topics under Social History & Conditions / Social problems / Social reform.
.D3 First Cutter number: An additional refinement of the subject (that special topic mentioned above), for Daylight Savings Time.
P74 Second Cutter number: For the author of this book, whose last name is Prerau.
2005 Year: This book was published in 2005.

This call number is for a book with the title Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time by David Prerau. The subject heading listed for the book is Daylight saving.