In his latest book, Under the Banner of Heaven, which he reads here, acclaimed chronicler of mountaineering extremes Jon Krakauer trains his reportorial eye on the extremes of religion. Through the lens of the Mormon Church and its fundamentalist fringe, he focuses on homegrown extremism by weaving the story of two fundamentalist brothers who claim they were motivated by God to slaughter their own sister-in-law and her infant daughter with the story of the founding and rise of the Mormon Church. Both stories are fascinating. The history of this fast-growing American church, only 170 years old, is well documented and now the brothers' brutal crime is, too. The author offers chilling insight into the "tyranny of intransigent belief," a tyranny that, as we all sadly know, has growing relevance worldwide. Krakauer understands extremism and how to capture its essence in vivid narrative.