There is much talk these days about lost books of the Bible. Sometimes people claim that the Bible was edited to take out reincarnation, or the teaching of higher planes of existence, or different gods, or ancestor worship, or "at-one-ment" with nature, anything that disagreed with what the people in power didn't like. But, none of this is true. The "lost books" were never lost. These so called lost books were already known by the Jews and the Christians and were not considered inspired. They weren't lost nor were they removed from the Bible because they were never in the Bible to begin with.
These so called lost books were not included in the Bible for several reasons. They lacked apostolic or prophetic authorship; they did not claim to be the Word of God; they contain unbiblical concepts such as prayer for the dead in 2 Macc. 12:45-46; or have some serious historical inaccuracies. These books were never authoritative, inspired, or authentically written by either the Jewish Prophets or the Christian Apostles.
Nevertheless, in spite of these problems the Roman Catholic church has added certain books to the canon of scripture. In 1546, largely due in response to the Reformation, the Roman Catholic church authorized several more books as scripture known as the apocrypha. The word apocrypha means hidden. It is used in a general sense to describe a list of books written by Jews between 300 and 100 B.C. More specifically, it is used of the 7 additional books accepted by the Catholic church as being inspired. The entire list of books of the apocrypha are: 1 and 2 Esdras, Tobit, Judith, the Rest of Esther, the Wisdom of Solomon, Sirach, (also titled Ecclesiasticus), Baruch, The Letter of Jeremiah, Song of the Three Young Men, Susanna, Bel and the Dragon, The Additions to Daniel, The Prayer of Manasseh, and 1 and 2 Maccabees. The books accepted as inspired and included in the Catholic Bible are Tobit, Judith, 1 and 2 Maccabees Wisdom of Solomon Sirach (also known as Ecclesiasticus), and Baruch
The Pseudepigraphal books are "false writings." They are a collection of early Jewish and "Christian" writings composed between 200 BC and AD 200. However, they too were known and were never considered scripture. A list of these would be the Epistle of Barnabas, the First Epistle of Clement to the Corinthians, the Second Epistle of Clement to the Corinthians, the The letter of the Smyrnaeans or the Martyrdom of Polycarp, the The Shepherd of Hermas, the The Book of Enoch, the Gospel of Thomas (140-170 AD), the The Psalms of Solomon, the The Odes of Solomon, the The Testaments of the twelve Patriarchs, the Second Baruch, the Third Baruch, the The Books of Adam and Eve.
The Deuterocanonical (apocrypha) books are those books that were included in the Greek Septuagint (LXX) but not included in the Hebrew Bible. The recognized deuterocanonical books are 1 Esdras (150-100 BC), 2 Esdras (100 AD), Tobit (200 BC), Judith (150 BC), the Additions to Esther (140-130 BC), the Wisdom of Solomon (30 BC), Ecclesiasticus (Sirach) (132 BC), Barach (150-50 BC), the Letter of Jeremiah (300-100 BC), the Susanna (200-0 BC), Bel and the Dragon (100 BC), the Additions to Daniel (Prayer of Azariah (200-0 BC), the Prayer of Manassesh (100-0 BC), 1 Maccabees (110 BC), and 2 Maccabees (110-170 BC).1
These pseudepigraphal and deuterocanonical books were never considered scripture by the Christian church because they were not authoritative, inspired, written by either Prophets or Apostles, nor do they have the power of the word of the books of the existing Bible. Therefore, since the books are not lost and were never part of the Bible to begin with, they have no bearing on the validity of the Bible.