Best way to make books?

Hello everyone,
I implemented books in my game, but since I found that there is no way to import .txt (or similar) files, I’m using .csv files in the same way they’re used for dialogues, by using a book ID, a page ID, and putting all the text in a cell. I don’t like very much this way, although it works, so I’m wondering if you found a better way, with a more appropriate file format, or something else?
Any suggestion is welcome!

If you want to keep it all outside of the engine and handle it separately, I would use sqlite which is a lightweight SQL server platform. Otherwords you can probably use variables with the individual books to store all of the text per-page.