If you look at the 66 books that are similar in both the Protestant and Catholic versions... there aren't any actual disagreements due to the writing. The verses would essentially be the same, depending on the translation, but the doctrinal differences come from differing interpretations of essentially the same words. (There isn't anything big, like the Protestant version having the words "do not ..." in a verse and the Catholic version having "you must do..." in the same verse or anything. We usually agree to be reading the same words, just interpreting them differently.) If you look at the 7 books that are in the Catholic Bible only, then -- as far as I know-- there is only one significant doctrine that can be found there that differs to the Protestant churches. And that is the doctrine of Purgatory, which is alluded to (not explicitly stated) in the book of Second Maccabees. The books are mostly history, proverbs, and story-telling. (The book of Judith is amazing, if you ever get a chance to read it.) Nothing really outrageous. They fit in well with the rest of the Old Testament. No big doctrines come from them. But where the Catholic and Protestant versions are the same, it's simply different interpretations of essentially the same words. When you get into different translations, then it's not really the verses that cause disagreement, but the footnotes/study notes by the editors interpreting the verses that cause the disagreement.