Duodecimo

A personal library, ready when you are.

Duodecimo brings 1,009 classic works to your iPhone and iPad. Every bundled book, its individual painted cover, and its reviewed reading guides are included for offline reading. No app account, advertising, paid content, or subscription is required.

Find a familiar favorite or discover something new. Book introductions, estimated reading times, and curated reading paths help you choose. Continue Reading keeps your current books close in Grid or List, while Want to Read gives the next ones a place of their own.

Add more books from Project Gutenberg. Search its catalog by title, author, or edition number, choose a language, and review the edition before downloading. Supported plain-text editions join your personal library with locally generated covers. Catalog and book downloads require an internet connection; downloaded books can then be read offline.

Settle into Book, Scroll, or Study, with fonts, spacing, margins, and appearance choices that suit you. Search the text, mark a page, highlight a passage, and keep your thoughts in a searchable notebook. Return to the source from your notes, export your commonplace book, or make a portable reading backup.

For bundled classics, Before You Begin offers context for every book. Who Is This Again? helps you recall people you have encountered, with reminders tied to passages you have already reached. These reviewed guides work offline without Apple Intelligence. On supported devices with Apple Intelligence ready, optional passage explanations and recaps use Apple's on-device models. Generated reading help can be inaccurate. Personal imports include the ordinary reader tools and on-device “What just happened?” recaps when Apple Intelligence is available. Curated Classics Companion guides and selected-passage explanations remain exclusive to bundled books.

Listen with Apple's installed system voices, choose a pace, set a sleep timer, and return to your saved listening place. Imported editions use a suitable installed voice for their language, or let you choose an installed voice explicitly. Set an optional daily reading target, look back over your reading calendar, and use the Continue Reading widget to open your book.

Optional iCloud continuity synchronizes supported reading data for bundled books. Personal imports and their reading data stay outside this synchronization. Portable reading backups include personal reading data and edition identifiers, but not book text; restoring an import may require the same edition again. Repair unavailable imports from saved source text when possible, or delete an imported book and its associated local reading data.

The bundled collection includes all six annotated volumes of Gibbon's Decline and Fall of the Roman Empire, the collected works of the American novelist Winston Churchill, and Sun Tzu's The Art of War in Lionel Giles's annotated translation.

The collection uses historical editions in the public domain in the United States. Source, edition, and license details are available in the app. Historical literature may contain mature themes, violence, and language reflecting its time.

The interface supports English and nine additional languages: French, German, Spanish, Italian, Japanese, Korean, Brazilian Portuguese, Simplified Chinese, and Traditional Chinese. Books, edition-specific source notes, and written reading guides retain their source language.