The Library Catalog
Understanding Call Numbers

While in the library or using our online library catalog you will notice most items have "call numbers" - letters and numbers indicating where they can be located in the library.

Most items at Middletown Thrall Library are filed according to the Dewey Decimal System, which divides all human knowledge into numbers from 000 to 999.

For example, Science can be found in shelves numbered 500 to 599, while Literature can be found between 800 and 899.

Some Dewey numbers are short, such as 123 DEF, while others may be longer, such as 123.678 ABC.

Reference items (beginning with REF) indicate a book can used at the library but not borrowed.

Most audiobooks at Thrall (except those in the Languages 400 section) begin with BCD.

Biographies are filed alphabetically by the subject's name, and their call numbers start with the letter B.

Children's items begin with J (for "juvenile") and can be found in the Children's Department.

Developmental Disability Materials begin with DDM are also available in the Children's Department

Fiction is filed alphabetically by the author's last name.

Government Documents are filed according to "SuDoc numbers." SUDOC stands for the Superintendent of Documents. Those call numbers are filed alphabetically by the government agency which published the documents: a document stored in the ED section came from the U.S. Education Department and a document stored under S came from the U.S. State Department.

Large Print materials begin with LP.

Music collection call numbers work according to ANSCR, or Alpha-Numeric System for Classification of Recordings. There are four parts (called "terms") to an ANSCR number. The first term pertains to the type of music; for example, a CD with opera music's first term will be B while a CD featuring a Broadway songs will likely be filed under K, while represents musicals in ANSCR. The second term pertains to the composer or performer. The third term is based on the album's title, and the fourth term represents the performer's last name, if any. An example of an ANSCR call number is

B 80

an example which represents the audio CD Mahler: Symphony No. 9, directed by Leonard Bernstein. A chart outlining ANSCR call numbers can be found in the library by our music CD collection.

New Materials have call numbers beginning with the words "Express Fiction" in the catalog. These new items are shelved in the New Books section across from the Circulation Department.

There are three sections in this area: Fiction, Nonfiction, and Biography.

Fiction is filed by author's last name, nonfiction by Dewey, and Biography by the subject's last name.

Nonfiction almost always is filed by the Dewey Decimal System.

Videos are filed in four sections:

Young Adult items begin with "YA." Young Adult nonfiction is interfiled with adult nonfiction. YA fiction is shelved separately.

If you have any trouble locating an item or interpreting a call number please speak with a librarian or ask us a question online.

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