"American Crucifixion" is well-grounded in its facts but reads more like a detective story or murder mystery. It's impossible to put down.
The Mormon church, aka: "The Church of Jesus Christ of the Latter-Day Saints," founder and "Prophet," Joseph Smith and his older brother Hyrum, the "Patriarch," were murdered in the Carthage, Illinois jail while awaiting trial. That they should have been murdered by an unruly mob should come as no surprise. The large Mormon community in Nauvoo (the second largest city in Illinois at the time) was not popular with the "Old Settlers." The events and prelude to their murder are well documented. What author Alex Beam has done is to describe the history in such a way that people and events are enriched at every step along the way.
The issue of polygamy as "revealed" to the Prophet is clearly the most central issue in the persecution of the Nauvoo-era Mormon community. Well beyond his twentieth and thirtyith plural marriage, (no one knows for sure how many), Smith continued to deny what he had done to the larger community, to most of his Mormon followers, even to his first wife, Emma who continued to stand by him. His entrusted his secret sealings to only a few of the most senior Mormons, "Apostles," as several of them would go on to embrace plural marriage themselves, or at least, not oppose it.
Beam provides a full post-murder history of the trial of Joseph and Hyrum's murderers. He goes on to give a history of the incredibly ineffectual Illinois Governor Ford under whose administration the murders occurred, as well as many other principals. In the final chapters, Beam explains Brigam Young's success in taking over the Saints, wresting church authority from the remaining members of the Smith family, especially Young's fall-out with Joseph's wife Emma and Joseph's eldest son, Josephy Smith III.