Index is a term used by librarians and scholars to describe a listing of sources. An index can be organized in several ways: by author, by subject or type of source, or by name of publication. For years indexes appeared only in book form, as in the Readers’ Guide to Periodical Literature and The New York Times Index. In the past decade hundreds of indexes have appeared in electronic form as well.

Database is a more recent term given to indexes. Databases are usually computer-based tools that allow you to access information in various ways. You can search easily by author, subject area, publication type, even by the language of sources and their available formats (PDF, full-text, for instance).

Technology has vastly expanded the size and arrangement of databases, giving you access to thousands of articles and resources that would have taken hours, days, even weeks to collect just a few years ago. Libraries purchase subscriptions to indexes and databases.

Electronic resources are developing quickly and in a number of forms. Some of these resources are discussed in Tutorial 4: Internet sources. This tutorial will focus on indexes and databases that lead you to sources in your chosen subject area.