EPUB Navigation

What is EPUB navigation? EPUB navigation is the system an ebook uses to guide readers through its contents. Imagine an EPUB (the file in an ebook) is like a large box. The box has smaller boxes inside of it, but you need to understand what the box and smaller boxes contain without opening them all.  Without the table of contents, you'd have to flip page by page to find what you're looking for.

Navigation tells you:

• What's inside the large box (book)?
• Where does each chapter (smaller boxes inside large box) start?
• How do I go directly to Chapter 10 (further down, inside more boxes)?

Instead  of digging through to find the box I want (Chapter 10), I can instantly discover where that box (chapter 10) is located. 

Example

• What it is: The linear list of files (spine) in an EPUB that dictates the reading order from start to finish.
• Comparison: Ants marching in a single-file line. Ants follow a strict linear path from the nest to the food source. You move straight ahead from one chapter file to the next in a set sequence, just as worker ants follow the trail step-by-step without skipping. 

• What it is: The structured hierarchical menu (nav.xhtml) that lets a reader jump directly to major chapters or sections.
• Comparison: Homing pigeons or migratory geese. Birds use a broad, high-level map of landmarks, stars, and the sun to pick a destination and fly straight there, bypassing everything in between. A table of contents lets you look at the big picture and fly straight to Chapter 5 instead of walking every page.

• What it is: Semantic markers in an EPUB (landmarks) pointing to critical structural spots like the start of the body, glossary, or bibliography.
• Comparison: Beaver lodges and scent posts. Beavers mark specific, important structural hubs in their territory—like the main lodge or the dam—so they can instantly locate vital zones of activity without searching the whole shoreline. Landmarks let a reading device instantly snap to the start of the story or the index.

• What it is: Inline links that jump to hidden, optional, or non-linear sections (like footnotes, answers, or game book choices).

• Comparison: A scout bee uses special movements to tell other bees the exact direction and distance to a new food source. The other bees read this dance and fly straight to the flowers without stopping along the way. The other bees break formation and leap straight to that exact spot, bypassing the normal sequential path of travel.

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Accessibility Evaluation

• If you would like to review recommendations to make your EPUB file accessible for readers, you can use the Accessibility Evaluation. This option is only available in the Book-Building Tool. 
• Click on Accessibility Evaluation on the left side of the screen. 
• Click on the button Start Evaluation.
• There is instructional information on the first pop-up. 
• Click "Next" to start the evaluation. 
• The first page will list all images in the Word file that you have uploaded that are missing alt text. 
  • There are four other sections you can proceed with that have additional recommendations for making your ebook more accessible to your current and future readers.
• While it is recommended to review all results, you can click Skip/Next until you reach the desired step in the evaluation.