Map EPUB Page Breaks to the Edition You Mean

Start with the named print object

A page number is meaningful only against an edition. Before adding page breaks to an EPUB, write down the print ISBN or other edition identifier, impression if known, and the pagination source. Do not map an EPUB to a paperback merely because their covers match. A reset preface, a revised introduction, or a different trim can move every later locator while leaving the title apparently unchanged.

Mark boundaries, not screens

A pagebreak marks the place before a numbered print page begins; it is not a report of whatever page a reader’s device displays. Give the marker a stable ID and an end-user page label. Then make the page-list link to that exact marker. The list may be optional in EPUB, but a mixed print-digital use case gives it a clear job: taking a reader from a citation or classroom instruction to the corresponding place in this edition.

Work a small sample first

Suppose a cited passage begins on print page 48 after an unnumbered half-title and Roman-numbered prelims. Place the `48` marker before the first word that begins that print page, not after a decorative chapter heading chosen for convenience. Check page 48, the next chapter opening, the first page after an illustration, and the final numbered page against the print reference. These four points often reveal a systematic offset.

Separate omission from mismatch

Do not invent missing page labels to make a neat sequence. Record pages deliberately unnumbered in the print source, and query any gap that cannot be explained by an illustration, foldout, or omitted material. If the EPUB has new matter, label the relationship in the edition note rather than quietly extending the print map. A page list is an access aid, not proof that two versions are textually identical.

Test the reader’s route

Open the page list where it is exposed, choose a middle entry, and confirm the target has the promised label. Also inspect the navigation document in the spine when secondary lists must be discoverable: DAISY notes that readers may not expose such lists otherwise. Preserve the page-map source and a short discrepancy log with the release candidate. Future correction then begins from a known map instead of a remembered one.

Give every discrepancy a disposition: corrected, intentional edition difference, or unresolved. A useful log says ‘print p. 96 begins mid-paragraph; EPUB marker placed before “But”’ rather than ‘page map checked’. That sentence allows another editor to reproduce the decision. It also keeps an EPUB made from revised text from borrowing the authority of a pagination source it no longer follows.