The 19th Wife by David Ebershoff

In 2004 BeckyLyn Scott, 19th wife of the current Prophet in the Utah community of First Latter Day Saints (known as the Firsts) is in prison for his murder.  In the summer of 1894 Ann Eliza Young, 19th wife of Brigham Young published a book called The 19th Wife exposing the reality of polygamy.  The two stories intertwine as Jordan, BeckyLyn's son, seeks to discover the truth behind his mother's arrest.  Lots of Mormon history, lots of exploration of the polygamous life style, and a pretty interesting mystery.  Jordan is an amusing and wise narrator of one story.  Ann is the guide to historical Mormonism on the verge of change.  It is a good compliment to Under the Banner of Heaven and an interesting insight into a belief most non-Mormons find hard to understand.