Why have an Index
A back-of-the-book index provides quick access to the terms and ideas found throughout a book. Potential book buyers know this and often check out the index to see whether the book meets their requirements.
Book buyers, Amazon.com, librarians, book reviewers, academics and educators all prefer books with indexes. Books with indexes have increased sales. Reviewers often comment on the index in their reviews.
The mechanics of book indexing is often underestimated as it involves meticulous work, accuracy, judgement calls and a good knowledge of indexing conventions. A professional indexer will produce a better index, and often faster too.
The author is too emotionally close to their book to write a good, objective index. A professional indexer has the training and expertise to make all the information in the book easily available to the reader.
Indexes require judgement calls and each index has varying challenges. Automatic indexing software can’t think and will only produce an index of limited usefulness and accuracy.
A good index is not one with long, undifferentiated strings of page numbers, no cross-references or wrongly linking cross-references, or a list of words generated by a computer. Indexing is not just creating a list of names and terms.
A quality index is one where the reader can quickly find what they are looking for, where concepts are linked and cross-references are used to guide the reader to related topics. An index is like a road map through the book detailing all the main streets and side avenues, with everything interlinked.
A quality index is accurate, easy to read and an asset to the book.