Under the Banner of Heaven by Jon Krakauer is a riveting exploration of religious extremism and violence. This bone-chilling narrative delves into a double murder committed by two Mormon Fundamentalist brothers who claimed divine inspiration for their actions.

Krakauer provides a meticulously researched account of this "divinely inspired" crime, weaving a multi-layered story of messianic delusion, polygamy, and unyielding faith. The book uncovers a shadowy offshoot of America's fastest-growing religion and raises provocative questions about the nature of religious belief.

The author takes readers inside isolated communities in the American West, Canada, and Mexico, where some forty thousand Mormon Fundamentalists believe the mainstream Mormon Church went astray when it renounced polygamy. These communities are led by zealots who answer only to God, defying civil authorities and the Mormon establishment in Salt Lake City.

Weaving the story of the Lafferty brothers with a clear-eyed look at Mormonism's violent past, Krakauer examines the underbelly of America's most successful homegrown faith, finding a distinctly American brand of religious extremism. This is a compelling work of non-fiction that illuminates an otherwise confounding realm of human behavior.