A call number is like an address: it tells us where the book is located within the library. Each book (or other item) has its own unique call number which is taped to the lower outside edge of the book’s spine.

A book’s call number also appears in the catalog entry in PowerCAT, the on-line catalog which lists the holdings of K-State Libraries. Note that the same call number can be written from top-to-bottom, or from left-to-right.

A call number is also a miniature subject formula:

Books are grouped by subject categories or classes. Each class is identified by a letter. Classes are broken down into subclasses by adding more letters. Subclasses are more finely delineated with numbers. Books are grouped together on the shelf, making it easier for you to browse the library’s holdings on a specific topic.

For a more detailed breakdown of the subject categories, check out the complete Library of Congress Classification Outline. (Note: These are PDF files, so you will need Adobe Acrobat to view them.)

Remember that the Library of Congress arranges materials by subject. The first section of the call number represents the subject of the book. The second section represents the author’s name and the last section is often the date of publication.

The first line of a call number may begin with one, two or three letters. These letters should be read alphabetically. A call number that begins with A is shelved before one that begins with B, C, etc.; and a call number that begins with QE is shelved somewhere between the one that starts with Q and the one that starts with QL.

Single letters are filed before double letters.

The second line of a call number is made of a number that may have one or more digits. This line is read numerically. A call number with a smaller number in its second line is shelved before one that has a larger number for its second line.

The third line is the trickiest part of the call number. The letter is shelved alphabetically, and the number following the letter is treated as if it were preceded by a decimal.

When the top three lines are identical, look to the fourth line. If it contains a letter followed by numbers, items are organized alphabetically by letter, and within each letter by decimal number. (Note the number is treated as a decimal number even though there is no visible decimal point).

The final lines of the call numbers may include dates, volume indicators, issue numbers, copy numbers and other annotations such as supplement or index specifiers. These annotations are read after the call number.

If you still can’t find what you want, ask for assistance at the General Reference Desk . The people who work there are always happy to help!