Knowledge Center

Clear answers for ebook production, accessibility, metadata, retailer readiness, and launch.

These guides are organized by the question an author is trying to solve. Technical claims link to primary sources wherever the standard or platform controls the answer.

EPUB & Production

What Is an EPUB File?

A plain-English explanation of EPUB, what is inside the file, and why it is the standard format for reflowable ebooks.

EPUB & Production

EPUB 3.3 Explained in Plain English

What EPUB 3.3 means for authors and publishers, what changed, and why a standards-compliant file still needs good production decisions.

EPUB & Production

Reflowable EPUB vs. Fixed-Layout EPUB

Choose the right ebook layout model based on what the content needs readers to control and what must remain spatially fixed.

EPUB & Production

What Is EPUBCheck and Why Does It Matter?

Learn what EPUBCheck validation can catch, what a clean report means, and what validation cannot tell you about reader experience.

Ebook Accessibility

What Makes an EPUB Accessible?

A practical explanation of the structure, navigation, text alternatives, metadata, and testing that make digital books easier to use.

Ebook Accessibility

How to Write Alt Text for Ebook Images

Write alternative text that communicates what an image contributes to the book without turning every picture into a visual transcript.

Ebook Accessibility

European Accessibility Act and Ebooks: What Publishers Should Know

A careful overview of the EAA’s relevance to ebooks, including why scope and exemptions matter before making blanket compliance claims.

Book Metadata

Ebook Metadata Guide for Authors

Understand the core metadata fields that identify, describe, categorize, and help distribute an ebook.

Book Metadata

BISAC vs. Thema: What Is the Difference?

A practical introduction to two important book subject-classification systems and why publishers may encounter both.

Book Metadata

Do Ebooks Need ISBNs?

When an ebook needs an ISBN, when a retailer may assign its own identifier, and why edition-level consistency still matters.

Retailer Readiness

Preparing an EPUB for Amazon KDP

What to check before uploading an EPUB to Kindle Direct Publishing and why previewing still matters after validation.

Retailer Readiness

Preparing an EPUB for Apple Books

A practical preflight for EPUB structure, metadata, images, accessibility, and previewing before Apple Books distribution.

Retailer Readiness

Preparing an EPUB for Kobo Writing Life

How to prepare navigation, validation, metadata, and images before publishing through Kobo Writing Life.

Retailer Readiness

Preparing an Ebook for PublishDrive

What to organize before uploading an ebook to PublishDrive: file format, contributors, metadata, cover, identifiers, and distribution decisions.

Book Launch

Book Launch Checklist: From Final Files to Long-Term Discovery

A practical sequence for coordinating production, metadata, retailer setup, author assets, outreach, launch content, and follow-through.

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