Mormon belief is based on the Book of Mormon, the Bible, and various revelations made to Joseph Smith during the course of his life. The Book of Mormon, which is ascribed to the prophet Mormon, recounts the early history of peoples in America from c.600 B.C. to c.A.D. 420. According to Mormon doctrine, these peoples were lost tribes of Israel who had immigrated to America and become the ancestors of Native Americans; they had been visited by Jesus and believed in him. Smith also asserted that God, angels, and human beings were members of the same species, and that God was an exalted Man. He also believed that Jesus was the only Messiah and that God and Jesus were two separate beings.
The Mormon's Aaronic priesthood (deacons, teachers, and priests), which includes every worthy male between the ages of 12 and 19, is primarily concerned with the temporal affairs of the church; that of Melchizedek (elders and high priests) is concerned with the spiritual leadership. High priests are represented in the Council of Twelve (the Apostles) and in the first presidency (the president and two counselors—three high priests vested with supreme authority). The territorial divisions of the Mormon settlements are wards and stakes. Each ward has a bishop and two counselors; five to ten wards compose a stake.
Significant characteristics of the Mormon creed include the emphasis on revelation in the establishment of doctrines and rituals, the interdependence of temporal and spiritual life, tithing, and attention to community welfare. Mormons practice baptism for the dead; they believe that the deceased soul may receive the baptism necessary for salvation by proxy of a living believer. They also believe in "celestial marriage," whereby individuals marry for all eternity. Mormons carry out a campaign of vigorous proselytizing which has, in the course of a century and a quarter, raised the church from a handful of followers to its present size.