While the Book of Mormon was initially deemed a production beneath contempt, and utterly unworthy the reception of a schoolboy, over time it has become apparent that if Joseph was the sole author he would have needed a deep understanding of:
However it is highly unlikely that Joseph would have had expertise in any of these areas, let alone all of them. So if Joseph did not have the expertise to write the Book of Mormon then who did? Who had the expertise to do what Joseph was not able to? Some early theories were that Sidney Rigdon or Oliver Cowdery were responsible but how do we know they had all the expertise and why is there no evidence at all of their involvement?