LESSON 5 CONTENTS:

Learning Objectives

Part One: The Organization of Library Materials

I. Preface to Part One

II. Subject Headings
* Subdivisions
* Types of Subdivisions
* Library of Congress Subject Headings

III. Classification Systems
* The Dewey Decimal Classification System
* The Library of Congress Classification System
* General Principles of Classification Systems

IV. Call Numbers

V. Part One Summary: The Complex Job of Organizing a Library

Part Two: The Online Catalog: Key to the Library’s Collection

VI. Preface to Part Two

VII. The Online Catalog – Key to the Library’s Collection
* The Structure of Online Catalogs
* Searching Online Catalogs
* The Peninsula Library system (PLS) Online Catalog

VIII. Key Points to Remember

Lesson Five Quiz

Lesson Five Exercise

PART 2: THE ONLINE CATALOG: KEY TO THE LIBRARY'S COLLECTION

VI. PREFACE TO PART TWO

As you saw in Part 1, organizing a library collection is complex and time-consuming. Finding what you need at the library, however, should not be difficult if you are aware of how to use the key to the library's collection: the online catalog, also known as the OPAC (Online Public Access Catalog).

The online catalog is a bibliographic database that lists every item within a library's collection and is one of the most important access tools used in research. It's referred to as an "online" catalog because individual computer workstations retrieve requested information from a main computer and display it on your screen. You're able to display basic details about every item owned by a library -- primarily books, but also audio-visual materials.

Before online catalogs, libraries maintained card catalogs in which thousands of
3 x 5 cards were kept in hundreds of file drawers. Starting in 1980, however, libraries began replacing card catalogs with online catalogs, until today card catalogs have all but disappeared. Although some people still mourn the loss of the old file cards, it is generally agreed that OPACs offer users more features and greater flexibility than card catalogs. Keyword searching is just one example of a search you can do with an online catalog but not a card catalog.

It is important to understand that OPACs do not index the contents of periodicals, i.e. they do not give you lists of magazine articles. You use a different access tool -- a periodical index such as the InfoTrac OneFile -- to search for citations to individual articles. (Lessons 6-7 will discuss periodical indexes in detail.) You can, however, use the OPAC to find out if your library subscribes to a particular periodical.