Structured books, metadata, identifiers and digital quality
Identify content, structure and presentation
A digital publication combines content, organization, metadata, assets and reading-system behavior. Structured authoring separates meaningful elements from a single visual layout so the same controlled source can support suitable outputs. This does not mean every conversion is automatically correct. Headings, reading order, references, tables, image descriptions and rights information need appropriate checks in each actual format.
Follow the package and reading order
An EPUB package describes relevant metadata, a manifest and a default reading sequence through its spine under the actual version. Not every file in the archive belongs in the publication-resource manifest, and a deprecated optional feature must not be described as mandatory for every current EPUB. Reflowable presentation adapts to relevant user and screen conditions, while a pre-paginated layout preserves a designed page relationship. Neither label guarantees identical pixel rendering on every device or complete accessibility. Validate syntax, references, navigation and actual behavior using appropriate tools and representative reading systems.
Use identifiers and metadata accurately
An ISBN identifies a publication product or edition under its actual assignment rules, not the copyright owner or proof of editorial approval. Its check digit can detect defined transcription errors, not every possible wrong record. In the stated thirteen-digit model, alternate weights one and three over the first twelve digits and choose the final digit that makes the total divisible by ten. Metadata about title, responsibility, language, product form and supply must describe the actual edition. A well-formed XML document can still fail an applicable schema or contain inaccurate business information.
Preserve usable and lawful delivery
Distinguish open reading, reusable licensing, access control and provenance marks. A watermark can support tracing without necessarily blocking copying; it does not guarantee authenticity or resist every alteration. A restrictive license can permit some sharing while withholding permission for commercial use or distributing adaptations under its actual terms. File conformance, rights and reader usability are separate questions. A print-exchange PDF variant does not guarantee error-free printing, and different variants permit different color-management features. These foundations do not replace Chinese publication administration, current format specifications, complete accessible-book assessment or the relevant subjective practical tasks.