American Millennials--the generation born in the 1980s and 1990s--have been leaving organized religion in unprecedented numbers. For a long time, the Church of Jesus Christ of Latter-day Saints was an exception: nearly three-quarters of people who grew up Mormon stayed that way into adulthood. In The Next Mormons, Jana Riess demonstrates that things are starting to change. Drawing on a large-scale national study of four generations of current...