Yes, it is OK to quote from a book in the interesting info. We ask that you don't ONLY use quotes from the book throughout your whole quiz, though. You don't need to reference the source if the book quoted is the one the quiz is about. It doesn't hurt to say which chapter you are quoting from, if applicable, but don't bother with page numbers. Too many of your players will have different editions, with different page numbers, so it's meaningless.