The legend tells us of Sacagawea ("Bird Woman") as the guide showing Lewis and Clark the way over the Rockies to the Pacific Ocean, and fictionalized accounts have embroidered on her life as it might have been. In fact, however, her life as it might have been. In fact, however, the young Indian woman who accompanied the expedition did not serve as a guide--though her presence with her child probably ensured the expedition's safety by signifying to the tribes whose territories were crossed that it was not a raiding or war party. This carefully researched historical account separates the...