In prophesying of the coming forth of the Bible, Nephi says concerning the contents of the book that "they have taken away from the gospel of the Lamb many parts which are plain and most precious" (1 Nephi 13:26). McConkie and Millet address the question, "What are some examples of these plain and precious matters which have been expurgated from the original biblical records?" May we not ask what became of such matters in the Old Testament as the identity of Jesus Christ as Jehovah, the ordinances of salvation (baptism, confirmation, sealings, and eternal marriages), the age of accountability, the premortal existence of man, the nature and functions of the Melchizedek Priesthood, the typology of the Law of Moses, and particulars concerning such doctrines as the Creation, the Fall, and the Atonement? These and a myriad of others--including such issues in the New Testament as the timeless nature of the Atonement (retroactive and proactive), the doctrine of celestial marriage, and a distinction between the destruction of Jerusalem in A.D. 70 and the signs of the times incident to the Second Coming -- were lost to the world until the "times of restitution" began in the spring of 1820. [Joseph Fielding McConkie and Robert L. Millet, Doctrinal Commentary on the Book of Mormon, Vol. 1, p. 98] [See the commentary on 2 Nephi 9:13; Jarom 1:2]
According to Clay Gorton, the books of the following prophets are mentioned but not included in the Bible: the book of Jasher (Joshua 10:13; 2 Samuel 1:18); the book of Gad the seer, (1 Chronicles 29:29); the book of Nathan the prophet (2 Chronicles 9:29); the book of Shemaiah the prophet (2 Chronicles 12:15); a writing from Elijah the prophet (2 Chronicles 21:12); the writing of Hezekiah king of Judah (Isaiah 38:9). [H. Clay Gorton, The Legacy of the Brass Plates of Laban, p. 17]