Uner the Banner of Heaven: A Story of Violent Faith (ISBN 1-4000-3280-6) is a book of investigative non-fiction written by Jon Krakauer first published in July 2003. It is a juxtaposition of two stories: the formation and evolution of the The Church of Jesus Christ of Latter-day Saints (Mormons), and a modern-day double murder committed by Ron Lafferty and Dan Lafferty in the name of God. The Laffertys were members of a splinter (or apostate) group that left the original Church when it ceased the practice of polygamy in the 1890s and call themselves fundamentalist Mormons. The book examines the ideologies of both The Church of Jesus Christ of Latter-day Saints and the apostate polygamy-practicing groups, such as the Fundamentalist Church of Jesus Christ of Latter Day Saints ("FLDS").