Got to be a pretty small book! (grin)
Anyway:
The Kingdom of Nauvoo by Benjamin E. Park
Kicked out of state after state, Joseph Smith and his followers bought land in Illinois on the shore of the Mississippi River. There, they built a community and began to live their lives according to Smith's teachings. As they grew in number, and rumors of what was going on there spread, they started making enemies. Missouri, for one, wanted Illinois to hand over Smith because they had some outstanding warrants for his arrest.
The big question that they were asking was if a state will not protect the religious liberty of its residents, would the federal government come to their aid?
Religious freedom was a big issue in the 1840s. The Mormons weren't the only sect trying to set up an independent community where they could be free from persecution.
Lake, however, doesn't get into that issue much. But this is still a worthwhile read, since he's taken advantage of the recent opening of the LDS archives to write an incredibly detailed history of Nauvoo. It's a good look at a forgotten part of American history.