Norman
Defender of Truth
From wiki:
The Spalding–Rigdon theory of Book of Mormon authorship is the theory that the Book of Mormon was plagiarized in part from an unpublished manuscript written by Solomon Spalding. This theory first appeared in print in the book Mormonism Unvailed [sic], published in 1834 by E. D. Howe. The theory claimed that the Spalding manuscript was at some point acquired by Sidney Rigdon, who used it in collusion with Joseph Smith to produce the Book of Mormon. Although Rigdon claimed that he was converted to the Latter Day Saint movement through reading the Book of Mormon, Howe argued that the story was a later invention to cover the book's true origins.
Contemporary Mormon apologetics state that the theory has been disproved and is discredited and argue that "few historians—whether friendly or hostile to the truth claims of The Church of Jesus Christ of Latter-day Saints (LDS Church)—believe that the historical data support the Spalding manuscript hypothesis."
Norman: Not true at all.
This interpretation initially appeared in the first anti-Mormon book, Mormonism Unvailed, a work published by Eber D. Howe and, most believe, authored by Philastus Hurlburt, an apostate. This hypothesis for the formulation of the Book of Mormon can best be summed up thus: “The Book of Mormon is the joint production of Solomon Spaulding and some other designing knave.” They conjectured this “knave” to be Sidney Rigdon.16
This explanation, originating in 1834, has been repeated by many anti-Mormon writers ever since. Because of this, Francis Kirkham spent a great deal of time in both volumes of A New Witness for Christ in America discussing this argument. The historical portion of the Book of Mormon, the proponents of this theory insisted, came from Solomon Spaulding’s novel, Manuscript Found. They contended that the fictionalized account became “scripture” as part of a careful scheme to defraud and deceive unthinking people. This explanation became an excuse for attacking the new religion. Brother Kirkham explained that, in addition to creating the Spaulding theory, Hurlburt gathered many affidavits from the residents of Palmyra, New York, talking of Joseph Smith’s ignorance, delusion, and superstition. This, the anti-Mormon writers believed, added additional weight to their “true” explanation of the origin of the book.
While this theory is still occasionally appealed to, most current anti-Mormon writers have abandoned this explanation. The reason is very simple. In 1884 the original of Spaulding’s Manuscript Found was discovered in Honolulu, Hawaii. When this document was then published, it very obviously bore no relation to the Book of Mormon. Significantly, the theorized link between the works of Joseph Smith and Spaulding was further discredited by Spaulding’s statement attached to the manuscript “that he did not accept the Bible as the revealed word of God to man” and that “the Bible’s only value is its ethical teachings.” Francis Kirkham pointedly proclaimed, “How could a confessed unbeliever in the Bible be the author of the Book of Mormon?”17
Brother Kirkham quickly refuted this argument, pointing out that Solomon Spaulding’s wife and daughter both stated that the Spaulding manuscript (the only one that would have been available for Sidney Rigdon to plagiarize) had been returned to the family from the printing shop where Manuscript Found was published. Later it was examined by Philastus Hurlburt—the anti-Mormon writer—who took the manuscript and never returned it despite repeated requests by the family.18
Source:
Francis W. Kirkham: A “New Witness” for the Book of Mormon - Ensign July 1984 - ensign