In 1804, Meriwether Lewis and William Clark, at the request of President Jefferson and Congress, set out on an unprecedented two-year journey up the Missouri River and across the Rocky Mountains to the Pacific Ocean. The purpose was see how far it really was to the Pacific and also to map natural resources with a view towards expanding the United states. The nation did not expect them to return and when they did, the information they brought back helped persuade Congress that expansion was not only necessary, it was mandatory. Their journals present a portrait of the unspoiled American West as only members of the Corps of Discovery (as their expedition was called) saw it. This landmark edition corrects spelling and grammar, retaining essential text and making the journals easy to read.