What a codex is, and whether you need one

The idea 
 A codex is the bible of your world: the characters, places, things, factions, rules, events and maps, each with a page of its own, and each page knowing what is true where and when . Write keeps one per universe, so every series set in that world reads from the same book of facts—and so does any AI you've connected, which is where a codex really starts to pay for itself. 
 If you've ever kept a spreadsheet of eye colours, or scrolled back three books to check which hand a character lost, this is that, kept for you. 
 Do you need one? 
 Not right away, and maybe not at all. A standalone novel with a dozen characters does fine with the notes panel—and notes have tags now, so they can be a small codex of their own (see Notes that become codex entries ). A codex earns its keep when: 
 
 you write a series, or several series in the same world; 
 facts change over time—a city falls, a captain is promoted, a name changes—and you need to know what was true in this book ; 
 you want an AI to check your continuity or draft with the world in mind; 
 you've lost track of something you invented, and it was important. 
 
 Start with notes. When a note wants to be shared across books, turn it into an entry; the rest of the codex can grow from there. 
 How it's put together 
 
 A universe is the world. It belongs to a pen name, and series join it. One universe, one codex. 
 An entry is one thing in the world: Tanis Richards , the Intrepid , Transcend . Every entry has a type—character, place, item, faction, rule, event, map, or one you've added yourself. 
 Each entry has a summary (one line), a body (as much as you like), and at-a-glance information : the fields on the right-hand side of its page, like the box on a Wikipedia article. Fields can hold general information, or information that applies only to one book, one series, or a stretch of time. 
 Calendars let a fact have a when . The codex starts with an ordinary Gregorian calendar; a science-fiction universe can add its own, with its own way of writing dates. 
 Mentions search your books for an entry's name and aliases, so you can see every scene a character walks through. 
 
 Where to find it 
 From the Library, Manage → Codexes lists your universes, each with an Open codex button. From inside a book, the Codex button in the editor's toolbar opens a rail that shows who and what the scene you're writing mentions, with a link to the whole codex framed to that book—see The codex while you write .