No Trail to Follow: The First Wagon Party to California, 1841 by Michael E. LaSalle

In May, 1841, an emigrant wagon party left Missouri and set out for far-off California. It had never been done before. Called the Bartleson-Bidwell party, its members would blindly grope their way across uncharted territory, with no idea of what to expect, what was ahead, what path to take, or how far they had to go. It was a landmark event in the settlement of the Far West. It was a miracle that they made it, and how they did it is one of the great stories in American history.

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