The Mormon handcart tragedy of 1856 is the worst disaster in the history of the Western migrations, and yet it remains virtually unknown today outside Mormon circles. Following the death of Joseph Smith, founder of the Mormon church, its second Prophet and new leader, Brigham Young, determined to move the faithful out of the Midwest, where they had been constantly persecuted by their neighbors, to found a new Zion in the wilderness. In 1846-47, the Mormons made their way west, generally following the Oregon Trail, arriving in July 1847 in what is today Utah, where they established Salt Lake City. Nine years later, fearing a federal invasion, Young and other Mormon leaders wrestled with the question of how to bring thousands of impoverished European converts, mostly British and Scandinavian, from the Old World to Zion. Young conceived of a plan in which the European Mormons would travel by ship to New York City and by train to Iowa City. From there, instead of crossing the plain...