The Catholic Bible is different from the Bible used by Protestants. While all 66 books found in Protestant Bibles are also found in the Catholic Bible, the Catholic Bible also contains other books, and additions to books. The Catholic Bible contains a total of 73 books, 46 in the Old Testament (Protestant Bibles have 39) and 27 in the New Testament (the same as Protestant Bibles).
The additional books in the Catholic Bible are known as the deuterocanonicals/Apocrypha. They are Tobit, Judith, 1 Maccabees, 2 Maccabees, Wisdom, Sirach (Ecclesiasticus), and Baruch. The Catholic Bible also includes additions to the books of Esther and Daniel. There was significant debate in the early Christian church, with a majority of the early church fathers rejecting the idea that the Apocrypha belonged in the Bible.
However, under tremendous pressure from Rome, Jerome, the translator of the Latin Vulgate, included the Apocrypha, despite Jerome’s insistence that the Apocrypha did not belong in the Bible. The Latin Vulgate became the dominant and officially sanctioned Catholic Bible, and remained that way for around 1200 years. Thus, the Apocrypha became a part of the Catholic Bible.
The Apocrypha was not formally/officially made a part of the Catholic Bible, though, until the Council of Trent, in response to the Protestant Reformation. The early Protestant Reformers, in agreement with Judaism, determined that the Apocrypha did not belong in the Bible, and therefore removed the Apocrypha from Protestant Bibles. The most popular English translations of the Catholic Bible today are the New American Bible, the New Revised Standard Version Catholic Edition, and the New Jerusalem Bible. Aside from the inclusion of the Apocrypha, each of these Bible translations is reasonably good and accurate in how it renders the biblical text into English.
In summary, the Catholic Bible is the version of the Bible promoted by the Roman Catholic Church and used by the majority of the world’s Catholics. Aside from the inclusion of the Apocrypha, the Catholic Bible is identical to Protestant Bibles in terms of the canon (the books belonging in the Bible).