An index is an alphabetical arrangement of information that is designed to help readers find information accurately and efficiency. Unlike the Table of Contents (which gives the reader a general overview of the book), the index identifies specific terms, concepts, and elements within the book that the reader cannot easily find if he or she were only to use the Table of Contents.

The index often contains various levels of subheadings. These allow the reader to refine their search from a very general topic to a more specific discussion about that topic. For example, if we wanted to learn more about “Arteries of the Heart,” we could look up the general term “Arteries.” However, a more time-efficient method would be to look up the subheading “arteries” under the discussion of “Heart”:

Heart, 209-235
arteries of, 209, 215, 222
conduction system of, 236, 259
shape of, 89, 102

This refined search has helped us quickly find the information we were searching for rather than reading the entire chapter from pages 209 to 235.

The toughest job for an indexer is knowing what information NOT to include in the index. Most books are filled with thousands and thousands of words. If an indexer is not selective, the index could end up being as large as the book. A good indexer sifts through these thousands and thousands of words to find the terms, concepts, and ideas important to your students, colleagues, and lay audience.