Why does my book need an index?
Who reads a reference book from start to finish? Well, some people may, but many more only have the time or inclination to dip in somewhere in the middle and extract the information that is relevant to them. Without an index, you will lose these readers.
An index is also a sign of quality. It tells the reader that the book is a serious work of scholarship. By the same logic, if the index is poor (by which I mean that it does not guide the reader easily and accurately towards the information they want), it conveys the message that the book itself is not worth the reader’s time and trouble.
Which brings me on to…
Why use a professional indexer?
The short answer is because we’re good at it!
The slightly longer answer is that a professional indexer has the training and experience to identify and list the book’s themes and ideas in a clear, concise and logical fashion, and to link them together with cross-references. A good index is not a mere list of terms (like a telephone directory) but a map that both guides the reader to where they want to go and suggests a few interesting detours along the way.
Indexers also have the skill to think like a reader. They imagine what terms the reader is likely to look up and then direct them to the terms the author prefers. They also know how to edit an index (boy, how we edit!) to ensure that it does not collapse under its own weight of terms or frustrate readers by referring them to scanty or irrelevant information.
These are all high-level cognitive processes, which explains why indexes (good ones) are still written by human beings and not by computers. And the more skilful the human being, the better the index. Stands to reason, really.
What is embedded indexing?
I have received a number of enquiries lately about embedded indexing. Some publishers, notably Cambridge University Press, are asking authors to supply manuscripts for typesetting and final editing that have an index included. Normally, the index is written at the very end of the publishing process from a finished 'locked' proof, but an embedded index can be produced at an earlier stage. This is because XE (Index Entry) codes are inserted - 'embedded' - directly into the manuscript text, and these translate into the page numbers that appear in the index. If new text is added, or text is removed, during a later edit, the embedded codes shift as well and index's page numbers update automatically.
It is possible to create an embedded index in Word, and there is plenty of guidance that is only a Google search away, but I don't recommend it. It's a laborious process, and so not very feasible for a full-length book. Instead, why not commission an indexer to take the strain? We have experience of this kind of work and the software that makes it easier.