At the time the books of the New Testament were written, many other pious stories and legends relating to Christ and His times were also widely circulated. As a result, in the early centuries of the Church, there was some confusion and doubt as to which books were inspired and biblical, and which were not. As far as is known, it was the Council of Hippo in A.D. 393 which first determined which books were inspired and were to be included in the Bible canon, a canon in every respect identical with the Council of Trent. Subsequent Councils confirmed this decision, and the Council of Trent, in 1546, formally canonized all the traditional books of the Bible. These books comprise the Old and the New Testaments, and it is a matter of faith for Catholics to believe that all passages of all the books are equally inspired.

Those books which were rejected by the Council of Hippo as being non-biblical belong to what is called the Apocrypha. These books treat largely of the incidents and events during the life of Christ not related in the books of the Bible. They are often well worth reading, as they offer much historical information not otherwise available. However, some of these stories have slightly heretical tendencies.  The Catholic use of the word "Apocrypha," as defined above, should be distinguished from the incorrect Protestants use of the word. Protestants use this term to designate the seven books of the Bible included in the Catholic Bible canon, but not accepted or found in Protestant Bibles. These seven books are: Tobit, Judith, Wisdom, Sirach, Baruch, 1 and 2 Maccabees, and parts of Esther and Daniel. Protestants call the books found in the Catholic Apocrypha the Pseudepigraphal books.

The difference in the Catholic and Protestant Bibles arose in the following manner. The Jews living in the few centuries before Christ were divided into two groups - the Jews dwelling in Palestine and speaking Hebrew, and the large number of Jews scattered throughout the Roman Empire and speaking the Greek language, a consequence of the conquest of Alexander the Great of Greece.

In the several centuries before the coming of Christ, the Jews in Palestine re-examined and eliminated some of the books from the existing collection as not in harmony with the Law of Moses and as doubtful inspiration. The Pharisees set up four criteria which their sacred books had to pass in order to be included in the revised Jewish canon: 1) They had to be in harmony with the Pentateuch (Torah or Law); 2) They had to have been written before the time of Ezra, 3) They had to be written in Hebrew; 4) They had to have been written in Palestine.

The application of these arbitrary criteria eliminated Judith, probably written in Aramaic; Wisdom and 2 Maccabees, written in Greek; Tobit and parts of Daniel and Esther, written in Aramaic and probably outside of Palestine; Baruch, written outside of Palestine; and Sirach and 1 Maccabees, written after the time of Ezra. By the 1st Century after Christ, this revised canon was generally accepted by all Jews.

From the earliest times, the Christian Church recognized the Jewish canon of the Greek-Roman tradition, or Alexander canon, as being the true Bible. Jesus Himself quoted from this Bible, and not until the Reformation was this canon seriously challenged. These seven disputed books are also called the deuteroncanonical books, while the rest of the books of the Old Testament comprise the protocanonical books. By protocanonical books is meant the "books of the first canon," books of the Old Testament accepted by both Christians and Jews. The deuterocanonical books, "books of the second canon," are those seven books found only in the Catholic canon. Luther rejected the deuterocanonical books of the Old Testament. At one time he also eliminated Hebrews, James, Jude, and the Apocalypse from the New Testament, but later Protestants reinserted them. Today the Catholic and Protestant new Testament books are identical.

Source: The New American Bible, Translated from the Original Languages.