Jon Krakauer takes readers inside isolated American communities where some 40,000 Mormon Fundamentalists still practice polygamy. Defying both civil authorities and the Mormon establishment in Salt Lake City, the renegade leaders of these Taliban-like theocracies are zealots who answer only to God. At the core of Krakauer's book are brothers Ron and Dan Lafferty, who insist they received a commandment from God to kill a blameless woman and her baby girl. Beginning with a meticulously researched account of this appalling double murder, Krakauer constructs a multi-layered, bone-chilling narrative of messianic delusion, polygamy, savage violence, and unyielding faith. Along the way he uncovers a shadowy offshoot of America's fastest growing religion, and raises provocative questions about the nature of religious belief.