I've got two books of the Lost Books sitting on the bookshelf FT. They're interesting reads. One is by, and don't quote me on this, Bart Erhlman. (?) He put together a book about the Lost Books, and then a book containing the lost books themselves. Oddly enough, these books have been revealed, authenticated, and anything else they needed to validate their authenticity, and I'm still unaware of The Church saying much about them. Especially since it's believed that they hold many texts in their own vaults, and have for decades, that authenticate them too.