July 9th, 2010 → 2:58 pm @ Michael Ferreira
Information is knowledge, and an index is a compilation of information designed to enhance the knowledge of your reader.
Think of the index as a roadmap for your book. Just as a roadmap gives you directions to reach your destination, an index gives you information in the form of headings, subheadings, and cross-references to answer your questions or help provide knowledge.
A Table of Contents will provide a quick overview of your book; but, an index will identify all important terms, concepts, and ideas and put them in an easy-to-use alphabetical format at the back of the book.
Indexes enhance sales and revenue for books. Readers who are happy with your book are more likely to purchase future editions.