The tragedy of the Donner party constitutes one of the most amazing stories of the American West. In 1846 eighty-seven people -- men, women, and children -- set out for California, persuaded to attempt a new overland route. After struggling across the desert, losing many oxen, and nearly dying of thirst, they reached the very summit of the Sierras, only to be trapped by blinding snow and bitter storms. Many perished; some survived by resorting to...