From the very first line of its title page, The Book of Mormon: Another Testament of Jesus Christ declares itself to be an ancient record. From the very first sentence, the weight of the text, this witness of Jesus Christ, is substantial. Over 500 pages long in the modern edition, the text itself unquestionably claims it is an ancient work (see the Title Page, introduction to 1 Nephi and 1 Nephi 1:1-3, to cite just three examples).
If the book was authored by Joseph Smith (or any other modern author), then it is simply false. Based on the claims of the text itself, I see no other option. The first line of the title page says the book is, "an account written by the hand of Mormon [a historical character from the book] upon [metal] plates, taken from the plates of Nephi [another character from the book]." Either this statement is true, or it is not.
Joseph Smith and those associated with him either lied and patently deceived the world about what the Book of Mormon was, or they unquestionably believed what they were saying. If they were deluded, then it was an honest (and quite unusual) delusion (three of Joseph's associates solemnly testified that they saw and heard an angel, saw the ancient Book of Mormon plates, and witnessed that they heard the very voice of God testify to them that the Book of Mormon record was true; eight of his associates testified that they saw and handled The Book of Mormon plates).
I know that The Book of Mormon: Another Testament of Jesus Christ is true. I know this because of what God has told me, personally. This book witnesses of Jesus Christ. It is significant evidence that Jesus Christ has set His hand again to recover His ancient covenant people.
