Sacagawea, a Shoshone Indian, was the only woman to participate in Lewis and Clark's expedition to find the Northwest Passage, a water route that was supposed to connect the Atlantic and Pacific Oceans. Sacagawea proved herself to be invaluable to the expedition, which was called the Corps of Discovery. During her travels with the corps, she helped them find food, negotiated for goods, and even saved important supplies when one of the corps's boats capsized. Book jacket.