The vast majority of non-fiction texts need an index to help readers find information. An index is not just a list of names of people or places that appear in the text, it is an analysis of the text that helps readers navigate through the text time and time again.

The job of the indexer is to analyse the text of a document so that users can:

• find information on a particular topic
• return to passages they remember reading
• scan the index to see what the document is about
• find out how particular themes or ideas are developed

And all without having to wade through long strings of page numbers.

As the Society of Indexers says “An indexer considers the terms the readers are likely to use and relates them to the language chosen by the author. An indexer analyses the meaning and significance of the entire content in detail, and identifies tangible concepts from the woolliest of descriptions. An indexer knows, for example, that tigers aren’t always tigers – they may also be referred to as ‘big cats’, ‘endangered species’, ‘maneaters’, ‘top predators’, ‘Panthera tigris’ and ‘poaching targets’. And an indexer, unlike keyword-based systems, will ignore such phrases as ‘unlike tigers’ and distinguish between Sumatran and Siberian species.”

Authors are often too close to their texts to be able to anticipate their users’ needs and lack the experience to compile adequate indexes. Contents lists may not make the links between sections of text that readers really want to know. An index need not add to book production time if it is planned into the production schedule, and the additional cost will add value to the volume because readers use indexes to compare the contents of books in stores and online.