Joseph Smith Jr. (1805-1844), a young farmer in Manchester, New York, reported in 1823 that an angel named Moroni had appeared in his bedroom directing him to a set of golden plates buried on the Hill Cumorah, four miles from his home. After four years of annual visits (1823-1827), Smith retrieved the plates in September 1827 and began translation. The translation process, involving Martin Harris and later Oliver Cowdery as scribes, took place primarily between April 1828 and June 1829. The book was printed by E. B. Grandin in Palmyra, NY, in a run of 5,000 copies published March 26, 1830, financed by Martin Harris mortgaging his farm.

The bulk of the Book of Mormon covers the history of the Nephite and Lamanite peoples, two factions descended from the Israelite patriarch Lehi, who the text says left Jerusalem around 600 BCE. The story begins with Lehi's prophetic call and flight, crosses the ocean to the 'promised land' (identified as the Western Hemisphere), and traces centuries of religious, political, and military history. Nephi and his brother Laman become the patriarchs of the two rival lineages; the Nephites are described as generally righteous and fair-skinned, the Lamanites as rebellious and dark-skinned. The narrative alternates between periods of righteousness, apostasy, warfare, and reconciliation, passing through the reigns of kings Benjamin, Mosiah, and various chief judges.

The book's theological and dramatic climax comes in 3 Nephi 11-28, when the resurrected Jesus Christ descends from heaven to a gathered multitude at the temple in Bountiful. He displays his wounds, invites the crowd to feel the marks in his hands, feet, and side, and over three days establishes his gospel among the Nephite-Lamanite peoples. He calls twelve disciples, institutes baptism by immersion and the sacrament, delivers a version of the Sermon on the Mount, heals the sick, blesses children, and prays with words the narrator cannot write. At the conclusion of the visit he selects three disciples to remain on earth until his Second Coming — the 'Three Nephites' of LDS folklore.

The Book of Ether, inserted into the narrative as a separate record translated by Moroni from an older source, tells the story of a people called the Jaredites. They emerged from the Tower of Babel at the time of language confusion, crossed the ocean in eight barges (with luminous stones for light), and established a civilization in the Americas long before the Lehi migration. The Jaredite record covers many centuries and concludes with a genocidal civil war at the Hill Ramah (identified in the text as the same hill the Nephites will later call Cumorah), in which two opposing armies annihilate one another in a single extended battle. Only one man, Coriantumr, survives to be discovered by the Mulekites (another migration group) and die among them.

The Book of Mormon's language is a sustained pastiche of King James English. 'And it came to pass' appears over 1,400 times; 'thee' and 'thou' are pervasive; verb endings in -eth are default. Isaiah chapters (2 Nephi 12-24, 2 Nephi 27, 3 Nephi 22) are reproduced nearly verbatim from the KJV, including italicized English additions the 1611 translators had flagged as not in the Greek or Hebrew sources. At the same time, the book contains extended chiasmic structures (Alma 36 is the best-known example) and other Hebraic poetic features that Mormon scholars have argued cannot be easily explained as nineteenth-century composition.

The 1830 edition included two testimonies: the Three Witnesses (Martin Harris, Oliver Cowdery, David Whitmer) attesting to having seen the plates and an angel, and the Eight Witnesses (four Whitmers, Joseph Sr., Hyrum Smith, Hiram Page, Joseph Knight Sr.) attesting to having handled the plates. All eleven left the LDS Church at some point; none retracted the witness testimony. Modern textual scholarship has traced the Book of Mormon's composition history, produced a Critical Text Project (Royal Skousen, from 1988), and analyzed its textual sources. The book's apparent dependence on the 1811 KJV, Ethan Smith's View of the Hebrews (1823), and Second Great Awakening religious culture has been central to critical accounts.

Within days of the Book of Mormon's 1830 publication, Joseph Smith formally organized the Church of Christ (April 6, 1830), later renamed The Church of Jesus Christ of Latter-day Saints. The movement expanded rapidly: Ohio (1831), Missouri (1838), Illinois (1839-46), and finally Utah under Brigham Young (1847-). Along the way the movement suffered persecution (the 1838 Missouri 'Extermination Order,' Smith's 1844 murder at Carthage Jail), developed distinctive doctrines (temple ordinances, eternal families, plural marriage), and split into multiple branches. Today the LDS Church claims over 17 million members worldwide; the Book of Mormon has been translated into 110+ languages with 200 million+ copies printed.