The following was taken directly from www.lds.org, which had this to say about the Bible:
The Bible is not God’s final revelation to humanity, however, and neither is this collection of sacred writings complete. The Bible itself speaks of other authoritative books of scripture including books of Nathan the prophet and of Jehu and Enoch, the prophecy of Ahijah, the visions of Iddo the seer, and even missing epistles of Paul (see 2 Chronicles 9:29; 13:22; 20:34; 1 Corinthians 5:9; Jude 1:14). Other books of Latter-day Saint scripture—the Book of Mormon, the Doctrine and Covenants, and the Pearl of Great Price—clarify the gospel as taught in the Bible and corroborate the truthfulness of the Biblical witness of Jesus Christ.
Is it true that these books were in fact supposed to be in the Bible, and yet are not?
These books mentioned as, "authoritative" books, while perhaps mentioned in passing in the Bible, (which not all of them are) are not missing, and were never intended to be in the Bible. For instance, in Acts 17, during his sermon at Mars Hill, Paul quotes a secular poet. Does this somehow make this poet "authoritative" or inspired?
The next question I would have is, if the Book of Mormon truly contains as it claims, "the fullness of the gospel", then why is it that not even one of these supposed missing books is found in all of the mormon doctrine? If the gospel was restored, and these books were authoritative, and divinely inspired, as is claimed, why is it then that they were never given to Joseph Smith?
The answer? They were not included in the Bible for the same reason other books were not. They were not missing, they were not supposed to be in the Bible! Not every ancient text is scripture, nor is it supposed to be in the Bible.
Something to think about!
In His service ...