Under the Banner of Heaven: A Story of Violent Faith is an investigative nonfiction book by best-selling author Jon Krakauer, first published in July 2003. It is a juxtaposition of two stories: the origin and evolution of The Church of Jesus Christ of Latter-day Saints (LDS Church), and a modern double murder committed in the name of God by brothers Ron and Dan Lafferty, who subscribed to a fundamentalist version of Mormonism. The Laffertys were formerly members of a very small splinter group called the School of Prophets, led by Robert C. Crossfield (also known by his prophet name Onias). The group accepts many beliefs of the original church at the time when it ceased the practice of polygamy in the 1890s but does not identify with those who call themselves fundamentalist Mormons. The book examines the ideologies of both the LDS Church and the fundamentalist Mormons polygamous groups, such as the Fundamentalist Church of Jesus Christ of Latter Day Saints (FLDS Church).