In 1984, Brenda Lafferty and her baby daughter Erica were found murdered in their Utah home, victims of a "removal revelation" that her Mormon brother-in-law had supposedly received from God. Krakauer (Into Thin Air) aims to explain why and how this crime happened by recounting the history of Mormonism from its conception by Joseph Smith in the 19th century and tracing the origins of its extremist sects through to the present day. Using current examples, Krakauer reveals that there are fundamentalist communities throughout North America and that although these sects are not recognized by the accepted Latter-day Saints (LDS) church (mainly because they still practice polygamy), they are able to exist unchecked by both the church and the U.S. government. The author's chronicle of the Mormon religion and its extremist offshoot is tempered by the very real and tangible story of Lafferty and her baby, whose lives were, in effect, taken by a fundamentalist faith. Krakauer, admittedly just trying to get to the heart of religious extremism, remains as impartial as possible toward his elusive and controversial subject, but the result is still unnerving. A thoroughly engrossing and ultimately startling comment on all fundamentalist ideas.