Mary E. Brown, Ph.D., Professor
Information Science

Southern Connecticut State University
501 Crescent Street, New Haven, CT 06515

Department of Information and Library Science
Fax: 1.203.392-5780 / Phone: 1.203.392-5781
Toll Free: 1-888-500-SCSU, then press 4

It is generally accepted that once about a dozen books are gathered together in a collection, some time of classification system is needed so users can more readily determine what is contained in each book.

In Unit One we learned that various aids are included inside books to help a reader know what is contained in a book and easily find certain information, such as tables of contents and indexes. While a reader might not mind checking the tables of contents or indexes of a few books to learn what information they contain, having to look through the a dozen or more each time information was needed would be inefficient if not stressful.

Before we had libraries of bound books, we had libraries or collections of clay tablets and scrolls. Clay tablets were likely to be to be stored on shelves. On the end of the clay tablet was an inscription telling the reader generally what that tablet contained. The row of shelving likely also had an inscription telling the reader generally what the tablets on those shelves were about. Scrolls might be stored on shelves or in clay jars. Each scroll likely had a tag tied to it with an inscription telling the reader generally what that scroll contained. The row of shelving or the jar container likely also had an inscription telling the reader generally what the scrolls on those shelves or in that jar were about.

Today we use classification systems such as the Dewey Decimal Classification System or the Library of Congress (LC) Classification System to label books and in this way generally tell the reader what the book is about. Likewise, the Dewey and LC Classes or classifications are used to label shelves of books so that a reader who understands the system (that is, what the letters or numbers represent) can browse for books on a particular topic simply by going to the shelves holding books with a given label. For example, if I wanted a book on mathematics I would go to the 500s in the Dewey system or QAs in the LC system. (You can also browse an online catalog in a way similar to browsing shelves in a library. Try it using an online catalog.)

For a fun review of the Dewey Decimal Classification System see http://library.thinkquest.org/5002/. For a more formal description of Dewey Decimal Classification see http://www.oclc.org/dewey/ For a description of the Library of Congress Classification System see http://www.loc.gov/catdir/cpso/lcc.html

Another way to identify information in books is through the use of Subject Headings. Queens College has a tutorial on Subject Headings at http://qcpages.qc.cuny.edu/Library/research/tutorials/booksearching/subjectheadings.php Clark State Community College also has a nice description of Subject Headings at http://lib2.clarkstate.edu/lc/subject.html.

Cloth is woven with two types of threads: the warp and the woof. The warp is the thread that runs the length of the cloth and between the two ends of the loom. The woof or welf is the thread that is shuttled back and forth across the warp. Classification systems, such as the LC classification system or the Dewey classification system or the Richardson classification system are the warp of library collections. In addition to giving an address or shelving location to each source, the threads or strands of the warp serve as divisions or classes of knowledge. With the classification number or call number of the division or subdivision of knowledge we seek, we can go to the appropriate location or address and browse for titles of interest. We may also use catalogues and search by author or title or subject heading to locate the exact address or call number of a specific item. Subject Headings such as LC subject headings or Sears subject headings are the woof of the collection. A given subject heading may be assigned to an item in philosophy as well as psychology as well as science. Subject headings allow us to find different perspectives of a topic by locating sources within each warp thread or division of knowledge that deals with that topic. Classification systems give permanent addresses to areas of knowledge. Subject headings are like breadcrumbs that are dropped where needed and allow us to take a sometimes-meandering journey through knowledge to see a topic both in familiar and new places. As with fabric, the woof (subject headings) and the warp (classification systems) give texture to the cloth or collection.