Yesterday, two people asked about the seven or so books which are in the Catholic Bible, but not in Protestant Bibles. There are two types.
#1. The Old Testament books that people like to drop are Tobit, Judith, Wisdom, Sirach, Baruch, 1 and 2 Maccabees. They are also parts of Esther, Daniel and Jeremiah that people leave out. Why?
We don't have any copies of those books in Hebrew. We only have the Greek translations. Because they aren't written in Hebrew, the Jewish people don't include them in the Bible. Protestant denominations follow their lead.
When the Dead Sea Scrolls were discovered in the 1940's, they found the original Hebrew versions of Tobit, Sirach and Baruch. I do not believe that Jewish people have made the attempt to put these books back in their Bibles.
Historical oddity: The story of Hannukah (a yearly Jewish festival) is contained in 1 Maccabees. It is part of the Catholic Bible, but not the Jewish Bible.
#2. The New Testament books that people like to drop are Hebrews, James, 2 Peter, 2 John, 3 John, Jude and Revelation. When the Bible was being compiled, these (and six other books) were accepted and used by about half of the Christians in existence, while the other half didn't accept them. Most of the debates of "which books should be in the Bible?" centered around these books.
But the main reason some Bibles don't include these books is because of Martin Luther. 1200 years later, he translated the Bible into German, and he tried to leave these books out, because they contradicted his personal philosophy. I think Lutherans are split, on whether or not to include them.