Transparency
Data Sources & Licences
We build this site from open data. Here is every source, its licence and the last refresh date.
| Source | Used for | Licence | Last refreshed |
|---|---|---|---|
| Wikidata | Publishers, literary awards & winners, literary magazines, typefaces | CC0 1.0 | 2026-10-02 |
| Wikipedia (English) | Introductory summaries; traditional and regional paper sizes | CC BY-SA 4.0 | — |
| Open Library | Subject statistics, publisher catalogue counts, edition data | Open data (CC0) | — |
| Project Gutenberg / Gutendex | Public-domain book metadata, download counts | Public domain metadata | 2026-10-02 |
| PGLAF mirror (gutenberg.pglaf.org) | Text file sizes used to estimate word counts | Public domain | 2026-10-02 |
| Google Fonts | Font family metadata | Open-source fonts (OFL/Apache/UFL) | — |
| International ISBN Agency | ISBN registration groups and ranges (RangeMessage) | Published for public use | — |
| ISO 216 / 217 / 269, ANSI Y14.1, JIS P 0138 | Paper size standards | Facts (standards cited) | — |
| Amazon KDP help pages | Spine factors, trim sizes, margin minimums | Facts (cited) | — |
| Brysbaert (2019), Journal of Memory and Language | Average reading speed | Cited | — |
| Leaf & Spine editorial | Guides, glossary, genre notes, book anatomy, bindings, paper types | © Leaf & Spine | — |
Attribution
Pages that show Wikipedia text link to the original article and carry a CC BY-SA 4.0 notice. Wikidata, Open Library and Project Gutenberg are credited on each page that uses them. Project Gutenberg is a registered trademark of the Project Gutenberg Literary Archive Foundation; this site is not affiliated with it.