The Apocrypha
The word Apocrypha, which means "secret/hidden," is an inexact description for the Biblical material more properly referred to as the deutero-canonical (or second canon) books.
Bibles used most commonly by Roman Catholics contain seven such books, as well as additions to the Old Testament books of Esther and Daniel. Those Bibles generally referred to by Lutherans sometimes include these as a section inserted between the Old and New Testaments, called the Apocrypha.
"Roman Catholic Bibles" place the books of Tobit and Judith between Nehemiah and Esther and 1 and 2 Maccabees after Esther. The books of Wisdom (or Wisdom of Solomon) and Sirach (or Ecclersiasticus) are similar to the Book of Proverbs and are placed after the Song of Songs. The book of Baruch follows Lamentations. Eastern Orthodox scripture includes these books, too, and some Orthodox Bibles contain still others such as the Prayer of Manasseh, Psalm 151, 1 Esdras, and 3 Maccabees (with 4 Maccabees as an appendix).
These books were not part of Hebrew scripture, but were included in all Christian Bibles until The 16th Century Reformation. The Reformers chose the shorter Old Testament of the Hebrew Bible (39 Books), thus paralleling the thought of Martin Luther who considered these other books "not equal to the Sacred Scriptures, but useful and good for reading."
Written during the three centuries before Jesus’ birth, they help fill out the story of the Jewish community during that time, and Luther, in his prefaces to several of the books, affirms that they are "useful" reading and can help to increase one's faith.
"About The Bible," Terence E. Fretheim, Augsburg Fortress, Publishers, 1999