In 382 AD, Pope Damasus laid out the books of the Old and New Testament. The same listing was promulgated at the Synod of Rome in 382, and again, at the regional councils of Hippo (393) and Carthage (397, 419). There were, and still are, 46 books in the Old Testament. When Martin Luther published his German translation of the Bible in 1517, he left out seven books. Why would he do that? Because the books in question didn’t line up with his new theology. At the Council of Trent in 1546 the Church reiterated her position on which books belonged in the Old Testament. Some protestants will point to Trent and claim that the Church added books in 1546 which just isn’t true.
The books missing from Luther’s Bible were: Baruch, Sirach, 1 and 2 Maccabees, Tobit, Judith, Wisdom. There’s an excellent article at Catholic Answers that goes into more detail about who did what and when, but the bottom line is that many of our protestant brothers and sisters are missing some pretty good stuff. Tobit is one of my favorite books of the Old Testament.
We Catholics refer to the seven books as deuterocanonical, a good word to know for trivia night. It means books that weren’t included in Hebrew Scripture but that are part of the Septuagint (The Greek version of the OT). Some of our non-Catholic brethren refer to them as apocryphal, a more negative term that means “of doubtful authenticity.
The Catholic Church has recognized all of the books of the Old Testament since at least 382. Your Bible is complete. Nothing is missing.