I've got a couple Prince for Books questions I hope someone can answer:

Is it possible to upgrade a standard Prince License for use with Prince for Books, or does it require an entirely separate license?

And is it possible to make Prince for Books behave exactly like ordinary Prince by e.g. unsetting a few options?

Prince for Books (PfB) is a special edition of Prince with some additional features requested by book publishers. You can download and try it from here:

https://www.princexml.com/books/

We are still working on the pricing model for PfB. Currently, we are leaning towards a per-title fee which would allow both small and large publishers to use PfB. Please contact us if you would like to use PfF to format your book!