In Under the Banner of Heaven: A Story of Violent Faith, author Jon Krakauer attempts to help readers understand why religious people perform heinous acts of violence. This text focuses on Mormon fundamentalists, specifically Ron and Dan Lafferty. These brothers are responsible for the murder of their sister-in-law and their niece. The two do not deny their crime, but they claim they are justified in their actions because they believe the murders were ordered by God.

Krakauer presents the story of the Lafferty brothers woven around the framework of the history of the Mormon Church. This history begins with the church's conception by Joseph Smith, then traces its peoples' bloody and violent search for a place to put down roots. This church history not only gives readers information about the beliefs of the early Mormon Church, to which the Laffertys were trying to return, but also gives information about the role of Mormons in American history. Krakauer presents this history in a winding fashion in which the story sometimes doubles back on itself, picks up another topic and then returns to the first topic.

The story of the Lafferty brothers is told beginning with a description of their childhood through their life in jail after the murders. According to the information provided by Krakauer the Lafferty boys' childhood was full of emotional turmoil because of the antics of their abusive, domineering father. As adults, the boys were easily swayed by the ideas of Mormon fundamentalism. The negative changes in Ron's behavior and personality as he searched for religious truth resulted in his wife leaving him. After his divorce, Ron became angry and volatile. Soon afterward, Ron began showing others a revelation he says was given to him by God. This revelation tells him to kill his brother, Allen's, wife, baby daughter, and two other people. After his trials, Ron is diagnosed by psychiatrists as having narcissistic personality disorder. Although this diagnosis indicates that Ron had some sort of emotional instability that precipitated his murderous acts, it avoids labeling Ron as insane since that label would indicate that anyone who "spoke" with God, including praying to him, could be considered crazy.