Navigation and reading order in an ebook
Ask an author about navigation in their ebook and they will point at the contents page. That is one of three things, and the other two are the ones that break.
A print book needs no navigation structure, because the object is the structure: the reader holds the whole thing, sees how much is left, and flips. An ebook has none of that. Everything a reader knows about where they are comes from structure declared inside the file.
The three things, and what each one does
The contents page. A page in the book, like any other page, that a reader can open and read. It lists the chapters and links to them. It is visible, it is yours to style, and it is the only one of the three a reader would describe as existing.
The navigation document. A separate structure the reading system uses to build its own menu — the one behind the contents button in the app, reachable from anywhere without leaving your place. The reader never sees your version of it, only what their app draws from it, which is why styling it is pointless and generating it correctly is not.
The reading order. The sequence the file declares: what comes next when the reader reaches the end of a chapter and keeps going. It is invisible, it is not the order the files happen to be named in, and it is the one nobody checks.
Those three are stored separately and can disagree. Nothing prevents it, and no obvious symptom announces it.
What it feels like when they disagree
Readers rarely report these accurately, because the experience is hard to describe. What you get in a review is that the book "felt broken".
- A contents entry that lands one chapter off. Every link works. Every link is wrong. The contents were built by hand against an earlier draft, and a chapter was added since.
- A menu missing half the book. The visible contents page is complete, so you never notice. The app's own menu stops at chapter twelve, because the navigation document was generated once and the book grew.
- Front matter after chapter one. The dedication and the epigraph sit in the reading order where their files were added, not where they belong. The reader turns the page at the end of chapter one and gets your acknowledgments.
- The book opening at the copyright page. The reader's first screen is a block of legal text and an ISBN. They will not call this a navigation fault. They will call it a bad start.
Where the three should come from
All three should be generated from the real structure of the book. Not one of them should be typed.
A manuscript with proper chapter structure — chapter titles that are headings, not big bold paragraphs — contains everything the three need, and all three can be derived from it consistently. That is the only way they stay in agreement.
A manuscript formatted by eye contains none of it. A chapter title that is 18 pt bold centered text is, to software, a paragraph. There is nothing to generate from, so the contents get hand-built, the navigation gets hand-built or omitted, and the reading order becomes whatever order the files ended up in. Three hand-built structures drift apart on the first revision.
In the Interior Formatter. It generates the contents from the real chapter structure of your manuscript rather than from a page you typed, and builds an EPUB 3 with chapter numbering, a declared language and ARIA roles already set. Start your ebook → · about the Interior Formatter
What belongs in the navigation, and what does not
Chapters, yes. Parts and major sections, yes — a reader in a long nonfiction book wants to jump to Part III, and Parts, sections and the pages between chapters covers how those behave in the book itself.
Every subheading, usually no. That overcorrection comes from treating the navigation document as an index. A menu with two hundred entries is not navigation; it is a wall the reader has to read to use. The test is whether anyone would want to arrive at that point directly. Chapter nine, yes. The third subsection of chapter nine, almost never.
Nonfiction with genuine reference use is the exception, and even there two levels is the practical ceiling. A reader who needs to reach two hundred specific points needs an index, not a longer menu — see Does your nonfiction book need an index? for the difference, and Indexes and cross-references in an ebook for what an index can be once the page numbers are gone.
A collected volume is the other place a second level earns its keep: set above book, book above chapter, so the menu shows five titles rather than sixty chapters. Bundling your ebooks into a set covers how that is built.
Landmarks, and where the book opens
Separately from the menu, a file can mark a small number of significant places: the cover, the contents, and the point where the actual text begins. Reading systems use those to decide where to open a book nobody has read yet.
Set them and the reader lands on chapter one. Leave them out and the reading system falls back to the first page in the file, which in a properly ordered book is the half title or the copyright page. What goes in the front of a book, and in what order explains why that front matter has to stay where it is — the fix is landmarks, not reordering the book.
This is the same work as accessibility
A screen reader uses exactly the structure described above: headings to move between chapters, the declared reading order to know what comes next, landmarks to find the start of the text. There is no separate accessible version of navigation. A book that navigates well is a book that is readable by ear, and a book with a hand-built contents page is unusable in both directions at once. Accessible ebooks, and why they are now everyone's problem covers the rest of that overlap.
Make your ebook
The tools are free to use: bring your manuscript once and get both a print PDF and an EPUB out of the same source, so the two editions cannot drift apart. You only pay when you want the files without the preview watermark.
Next: Checking an ebook before you publish it · More: Does your book need a table of contents? · Links in an ebook, and where they should point · Converting the ebook yourself, or paying someone