One of the most gruesome episodes in the history of the American West was the trek of the Donner Party in the 1840s. Irish immigrant Patrick Breen was among those headed to California when the group came upon snow so deep they were unable to continue. As he wrote in his diary: "We now have killed most of our cattle, having to stay here until next spring." Almost 50 of the 100 or so Donner travelers died, and some of those who lived likely resorted to cannibalism. Now a full-scale history, entitled "Desperate Passage: The Donner Party's Perilous Journey West," has been written by Ethan Rarick. Using new archaeological evidence, and other groundbreaking research methods, not to mention the heartbreaking letters which survived, Rarick acts almost as an historical detective, overturning many previously believed notions regarding the Donner Party. In the end, Rarick writes, "this is a story of hard decisions that were neither heroic nor villainous. Often, the emigrants displayed a more realistic and typically human mixture of generosity and selfishness, an alloy born of necessity." ($28 / 304 pages / Oxford University Press)