Do I need an index?
Reading a nonfiction book without an index is like being in a strange town without a map. Sure, you can have a good wander around and enjoy the sights. But if you need to find your way to anything specific, you're going to struggle.
If you're writing a complex nonfiction book then including an index is typically a good move. And if you've ever spent ages flicking through a dense book to find a reference, we're sure you'll agree. That said, shorter books, or those with a very detailed contents page, should work perfectly well without one.
What does it actually do?
An index is different from a contents page. Instead of displaying the general structure of a book, it signposts you to the details: the important words, terms, and topics hidden inside. Readers use an index to quickly navigate to sections that contain information they're looking for.
When browsing books in a bookstore, a reader will often turn to the index to check if the book covers the topics that interest them. It's a good way to see the scope of a book at a glance. If they can quickly see it's going to be a good resource, they'll buy. If not, they move onto the next book on the shelf.
Who creates the index?
Some authors might assume that their book designer will create an index during the design and typesetting phase. Indexing is a highly specialized skill, however, and beyond the scope of your designer or publisher. No computer software program can replace the professional skills of a good indexer. Never leave it up to your book designer or proofreader, especially if they offer to "have a go." It's a surprisingly tricky business.
An indexer begins work once a designer has typeset your book and set all the page numbers. They'll read the entire book from start to finish with the detachment of a reader. A proper index is not just a list of commonly used keywords in your book: it picks out the concepts and terms behind those words. For example, you may not always refer to a cat directly as "cat" in the text. You may also use "kitten," "pussycat" or "feline." An indexer will know that a reader is most likely to think of "cat" first, and make sure all those alternate terms are listed under it.
You may need to book them several weeks in advance, which is why it's worth thinking about this early. As soon as you have an idea of when the designer will be finished with your book, get your indexer booked in.
Can I do any of it myself?
If your book is not overly complex and funds are tight, you could consider indexing your book yourself. If you are a confident user of Microsoft Word, you can add index entries, or XE fields, to your manuscript using Word's referencing tools. You can do this as you write, or add them all at the end. Word and InDesign can then take care of quite a lot of the donkey work, gathering the marked entries, alphabetizing them and keeping the page references up to date.
Another DIY method is a concordance file. This is not a true index: it won't, for example, organize your content by themes, topics or relationships. Word will simply pick out every use of a particular word and give a list of page numbers alongside. It won't make an allowance for context or usefulness, or differentiate between different forms of the same word. As a tool, it's rather blunt and unsubtle, so you may need to use it with care and low expectations.
And in case you were thinking AI could do your index, not yet, I'm afraid. It can pick out words and suggest topics, but a good index is about understanding what a reader might look for and how all those ideas relate to each other. The American Society for Indexing has tested AI-generated indexes and found that they still need so much checking and correction that they can create as much work as they save.
How about typesetting the index?
However you decide to create your index, once it's finished, you can hand it back to your book designer for styling. They'll add the index to the back of the book and typically lay it out in two columns using a smaller font. They'll also style it with hanging indents so that readers can see each indexed word and its subentries easily down the left side of the page.
What about ebooks?
The page references in your printed book index won't make sense when you convert your book to an ebook. The amount of text on an ebook "page" isn't fixed. It flows to fill the screen according to the screen size and the reader's settings.
There's no need to panic, however. A good ebook conversion knows how to handle the index properly, linking readers to the correct positions in the ebook rather than relying on fixed print page numbers.
Getting your index right
Deciding to include an index at the back of your nonfiction book will add enormous value. Your readers will love you for helping them find and explore complex topics. However, this does all depend on you creating an index that's high quality, intuitive, and comprehensive.
A professional indexer is definitely the best way to go if you can. Once it's ready, we can add and style your finished index as part of our book formatting service.