We occasionally refer to the process of digitally extracting all the people, places, and things mentioned inside of a book as ‘indexing’ it.
For example, on your Storyboard page when you move your mouse over a book cover you may see a bubble that says "NOT YET INDEXED" which means we've added the basic information for the book (cover, title, description, etc.) but have not yet mapped all the passages that contain people, places or things in it. In contrast, if you see a bubble on a book cover that says "FOUND IN THIS BOOK" you're able to see how many people, places, and things have been 'indexed.'
We index books in a combination of automated and manual steps to combine scalable detection of terms with human oversight to verify and improve the overall system. If you’re interested in helping with the human aspect, please let us know!