Much of the earlier part of Howe's book is taken up with a long examination of the contents of the Book of Mormon. Howe made point after point against the book's authenticity; and the points remain compelling today. He went on to recount some of the early history of the Mormon Church as a small but growing charismatic end-times sect. He also published nine letters from Rev. Ezra Booth, a Methodist minister who had briefly got mixed up with the Mormons. Booth paints a picture of Joseph Smith as an authoritarian fake prophet ruling over a bunch of dupes who saw visions and spoke in tongues while they waited for the end of the world.
Most importantly, however, Howe's book contained 30 affidavits from people who were in a position to shed light on the origins of the new religion. These affidavits relate mostly to Joseph Smith's background and career before he became a prophet, and they represented one of several attempts made during the 19th century to gather witness testimony about Smith's early life. (The best general survey of these attempts by a non-Mormon scholar is Joseph Smith’s New York Reputation Reexamined by Rodger I. Anderson.)
The affidavits in Howe's book were collected by a curious fellow by the name of D.P. Hurlbut. Hurlbut was a disaffected ex-Mormon and a somewhat shady character. There is no doubt that he set out to pull together the most unfavourable testimony he could find. Mormon scholars have accordingly attempted to write him off as a liar and to dismiss the content of the affidavits.
This is a little too easy, however. The fact remains that a series of people who had known Joseph Smith personally were prepared to go on record with public, sworn testimony against him. This is a real problem for Smith's defenders. It is unlikely that the affidants engaged in an act of mass perjury at the behest of an unknown outsider like Hurlbut. It is also worth noting that Howe was not a fool, and that he personally verified a sample of the affidavits.
In summary, the affidavits tell us that:
- The Smiths were seen as being of poor character and dishonest.
- Joseph personally was seen as being of poor character and dishonest.
- The Smiths were involved in folk-magic and clairvoyant treasure-hunting.
- In this context, Joseph had claimed that he was able to see buried treasure and spirits using a stone placed in a hat.
- Joseph later used the same stone to produce the Book of Mormon.
For a number of reasons (some of which are summarised by Vogel), most modern scholars have concluded that the Book of Mormon is probably not based on a Spalding novel. It is more likely to have been written by Smith himself. For what it is worth, the only surviving copy of a Spalding novel, the so-called "Manuscript Story", is very different from the BoM. Yet eight witnesses testified that the BoM resembled in detail a novel which Spalding had shown or read to them during his lifetime. This mistake can be attributed partly to fading memories - it was 20 years since they had last seen or heard Spalding's work - and partly to a willingness to go along with some over-eager prompting from Hurlbut.
Inevitably, the fact that some of Howe's affidavits endorse the Spalding theory has led some Mormons to cast doubt on everything that the affidavits say. But this is unwarranted. Only eight out of 30 witnesses referred to the matter, and those who did so were probably not dishonest - just willing, with Hurlbut's encouragement, to put two and two together to make five. In any case, the most interesting parts of the affidavits relate not to a dimly remembered novel from 20 years earlier but to the recent antics of a colourful young man who was personally known to most of the affidants.
Howe made mistakes and wrote in a somewhat dated and rhetorical style; but the contents of his book have held up remarkably well over 180 years. Mormonism Unvailed still remains a useful source of information on Joseph Smith and the beginnings of Mormonism.