LOST books of the Bible
Question: Are there lost books, inspired by God, that ought to be in the Bible? There are several scrolls that exist which claim to be written under inspiration.
Answer: Your question is broad and much could be written on such books. Although this is only a brief answer to your inquiry about supposedly "lost" writings that should be in the Holy Scriptures, further research is suggested.
There are valid reasons why certain writings, though supported by some, are not inspired by God, and therefore are rightfully not included in our modern translations. Usually the reason for rejection is that the "lost" writing in question contradicts the facts presented and accepted teachings confirmed by the already accepted scriptures.
For example, one writing called St. Thomas' gospel teaches things that are contrary to sound Biblical doctrines. It teaches that God had TWO distinct creations of man, one that was a bit flawed, and the other that was perfect. This "gospel" also promotes the idea that people can acquire the "image of God." Scholars and those who study God’s holy word view this spurious writing with skepticism. Only a small cultic following that thinks it portrays the 'real Jesus' and that it is more accurate than the accepted four gospels.
Many of the larger and more expensive translations contain a section of the so-called "Apocrypha." These are writings that some in the past thought should have been included in the canon but were excluded. Many of them will have their history in their introductory remarks. Books printed by Catholic-centered publishers are often the most comprehensive in this area.
Several reference works offer information regarding why certain writings were excluded from scripture, the discovery dates of the writings and so on. The title of two of them is Lost Books of the Bible by Solomon J. Schepps and William Hone and The Forgotten Books of Eden, which is an anthology of ancient, apocryphal writings. The latter of these two volumes is especially comprehensive. Together, these works discuss the writings below that various people argue should become part of holy writ.