Presence: Which Books a Character Is In
In a series, your cast is shared. There's one Sherlock Holmes for the whole series: edit his page once, and he's up to date in every Book. Presence is simply the list of Books a character, item, or location appears in.
Setting Presence
You'll find the Presence field on each character's page, and in the panel that opens when you click an item or location. It's a list of your Books with a checkbox next to each; tick the ones this character belongs to. Sherlock might be present in all three Books, while a one-off witness only appears in Book 1. Unchecking a Book doesn't delete anything; it only takes the character off that Book's lists. Check it again and they're right back, exactly as they were.
New characters, items, and locations start out present in the Book you're currently in. If Sherlock turns out to matter in Book 2 as well, just add Book 2 to his Presence.
Note: Every character, item, and location must appear in at least one Book. When only one Book is left checked, that last checkbox locks. To remove a character from the series entirely, delete them from the Characters page; Penpoint asks you to confirm first.
Presence vs Chapter Assignments
Presence says "this character belongs to this Book". It controls where they show up: the Characters, Items, and Locations pages, plus the matching lists in the writing-mode sidebar. Assigning a character to a chapter is a more detailed note about exactly which chapters they appear in. Mentioning a character in a chapter doesn't change their Presence.
Presence is what the This Book view filters on; see This Book vs All Books to control which part of your cast you're looking at.
Presence decides whether a character shows up in a Book at all. How much they matter in the Books they're in is a separate setting, kept per Book: see Importance Across Books.
Tip: Notes, Tags, and Series Arcs don't have Presence; they belong to the whole series, no matter which Book you're in. Character Arcs don't have a Presence field either: they follow their keyframes (the chapter moments that plot the arc), appearing in whichever Books those chapters belong to.