Does your nonfiction book need an index?
Answer honestly, because an index is real work and a bad one is worse than none.
A book people consult needs an index. A reference book, a how-to book, a history, a biography, a serious work of ideas — these are used as well as read. Somebody remembers a passage about the 1974 strike, or the section on pruning, and needs to get back to it. Reviewers in some fields note the absence, and librarians largely expect one.
A book people read straight through does not. A memoir, a narrative essay collection, a novel, a short practical book you finish in an evening. Nobody looks anything up in them, and an index at the back is pages nobody opens.
If you are unsure, ask what a reader does the week after they finish. If the answer is "puts it on a shelf", skip the index.
An index is a map of concepts, not a list of words
An index is not a record of where words appear. It is a curated set of entries naming the things the book is about, pointing at the pages where each is discussed, under the words a reader would think to look for.
That means a judgment on every line. A chapter that argues about inherited wealth for nine pages without once using the phrase still gets an entry under it. A page that mentions Rome in passing does not. Two names for one idea get a single entry and a cross-reference from the other. Big subjects break into subentries, because twelve page numbers in a row after one heading is not a map.
Which is why an automatic word-frequency index is worse than having none. It lists every occurrence including the trivial ones, misses every concept discussed without its keyword, and cannot tell a passing mention from the nine pages that matter. It also looks exactly like a real index, so the reader trusts it, follows it to a page that says nothing useful, and concludes the book is badly made. If you cannot index properly, leave it out and use one of the alternatives below.
It is built against final page numbers, and that is the schedule
The most important fact about an index is when it happens: last.
An index points at page numbers, so it can only be made once those numbers are real — after the interior is composed, proofread and final. And it breaks the moment the book re-flows. Change the body typeface, adjust the margins, add a paragraph in chapter 3, switch the trim size, make a large print edition: every page number after the change is now wrong, and the index has to be redone rather than patched.
So the order is fixed. Finish the manuscript. Compose the interior. Proofread it and make every correction. Only then index.
The index's own pages are the safe part, because they sit at the back, after everything they point at, so adding them shifts nothing that is indexed. But they do add to the total page count, and page count sets spine width — so the cover is finalized after the index, not before.
In the Interior Formatter. An index is built against composed page numbers, so it comes after the interior is final — and the final page count, index pages included, flows to the Cover Maker, which computes the spine from the real book. Start a book → · about the Interior Formatter
The alternatives are often better
For most independently published nonfiction, one of these serves the reader better than an amateur index, at a fraction of the effort.
A detailed table of contents. If your chapters have real sections and you list the second-level headings, the contents becomes a usable map of the argument. For a how-to book this is frequently all a reader needs, and it comes from the book's own structure rather than a separate pass.
A glossary. If the difficulty in your book is vocabulary — technical terms, foreign words, a cast of unfamiliar names — a glossary answers the question a reader actually has. They do not want the page where a term first appeared. They want to know what it means.
A searchable ebook. Search is not an index, because it finds words rather than subjects, but it is good at getting a reader back to a half-remembered passage. A well-structured EPUB with real chapter navigation, proper headings and a live contents gives most of what an index would have been used for.
Running heads that say something. A chapter title across the top of the page lets a reader flicking through land in roughly the right place, and makes a reference book much less frustrating.
A page-number index in an ebook is meaningless
In a reflowable file there are no fixed pages. The reader sets the type size and the device decides where each screen ends, so "page 212" refers to nothing. An index of page numbers pasted into an EPUB is dead text: it looks authoritative and every number in it is wrong.
There are two honest options. Turn each entry into a link that jumps to the place in the text — a real ebook index, more work than the print one and rarely worth it outside reference publishing. Or drop the index from the ebook and let readers use search and the contents, which is what they will do anyway.
What you must not do is ship the print index unchanged. A screenshot or a page image of it is worse still: not searchable, not clickable, and a blank rectangle to anybody using a screen reader.
If you do want a real one
Professional indexers exist, they are trained, and they work from proofs. Hiring one is the normal path, and the fee usually scales with page count and the density of the subject. Budget for it in the schedule as well as the money: the indexer needs final pages, and the book waits.
Doing it yourself is possible for a modest book. Read the final proofs as a reader looking for things rather than as the author, and note the subject of each passage, not its words. Keep asking what a stranger would look under, and give them a cross-reference when the answer is more than one thing. Then check every page number against the finished pages.
Make yours
Everything here is built into the tools, and they are free to use: name your book, bring your manuscript or your artwork, and work as long as you like. You only pay when you want the files without the preview watermark.
Next: Footnotes, endnotes and the reader's patience · Also in this guide: Does your book need a table of contents? · The back of the book is where your next sale is · Accessible ebooks, and why they are now everyone's problem