Fundamentalists believe they are following the "true" Mormon faith as laid down by founder Joseph Smith, while the mainstream Church of Jesus Christ of Latter-day Saints is "out of order" because of its disavowal of plural marriage, the United Order and other early doctrines.
The LDS Church's 1978 decision to give the priesthood to black men, in particular, galls fundamentalists. Special Report
But it is their marriage views that are most often noted by outsiders.
All trace their priesthood authority to conduct plural marriage back to LDS Church President John Taylor, whom they say had the doctrine confirmed to him in a 1886 revelation.
Fundamentalists believe monogamy is limiting for both men and women -- men because their sexual drive enables them to father more children than one woman can bear, and women because a certain percentage will never find a worthy man to marry and thus be unable to fulfill God's edict to "be fruitful and multiply and replenish the earth."
Plural marriage allows a man and his "ladies" greater opportunity to provide bodies for waiting heavenly spirits and increases their ability to populate this and future worlds; righteous plural marriage brings access to the highest degree of the Celestial Kingdom.
This belief aside, Utah's three largest fundamentalist groups have developed distinctive cultures. The FLDS church is the most restrictive when it comes to lifestyle.
Independent fundamentalists believe these organized groups are in error given early counsel to avoid structure or collection of tithing.