basically what it is
Whereas your catholics and christians have the old and new testaments, the Mormons have a thrid called the book of Mormon or something like that. Its basically about God dealing with the Americans before the birth of christ up to the present day and stuff like that.
Apparently:
"The Book of Mormon was written by many ancient prophets in the spirit of prophecy and revelation. Their words, written on gold plates, were quoted and abridged by a prophet-historian named Mormon. The crowning event recorded in the Book of Mormon is the personal ministry of the Lord Jesus Christ among the Nephites soon after his resurrection. It puts forth the doctrines of the gospel, outlines the plan of salvation, and tells men what they must do to gain peace in this life and eternal salvation in the life to come."
And:
"The Book of Mormon purports to tell the history of peoples in the Western Hemisphere from before the time of Christ. The emphasis is on two "migrations" of people from the Middle East to somewhere in North, Central or South America. (The specific details in the Book make it impossible to pin down exactly where all of the events were alleged to have occurred.) The first group of migrants, the Jaredites, were depicted as making the trip around the time of the Biblical Tower of Babel incident. Their civilization in the New World grew, flourished, then disappeared before the arrival of the second wave of immigrants.
Most of the Book of Mormon is about this second group, which became a great civilization flourishing from about 600 BC to 400 AD. According to the story, a "prophet of God" named Lehi left Jerusalem just before the fall of that city to Babylon, around 600 BC. He sailed across the Indian Ocean and the Pacific with his wife Sariah, sons Laman, Lemuel, Sam and Nephi, and a few others. They also settled down somewhere in the New World and created a flourishing civilization. On Lehi's death, the people divided into two warring tribes, one led initially by Laman, the other by Nephi. Much of the Book of Mormon deals with their disputes and wars. The Nephites are portrayed as primarily good, the Lamanites as primarily evil. At one point, the Lamanites are cursed with "dark skin," and are believed by the Mormons to be the forebears of the Native Americans. By the end of the Book of Mormon, the Nephites have been almost totally destroyed. Their last leader, Mormon, compiles the history that is to become the Book of Mormon, and inscribes it on golden plates. His son Moroni is the last living Nephite. This Moroni shows up 1400 years later as an "angelic messenger" to tell Joseph Smith the location of the plates. "
Although how this translates into being able to marry several of your cousins, not drink coffee or tea and wear black all the time is beyond me. Personally, im Roman Catholic so i think the whole moron thing is all bull$hit anyway