The chapters in this book are organised to represent different segments of the route followed by the Corps of Discovery across Idaho, Washington and Oregon. The first chapter describes their crossing of the Continental Divide -- three times on the way west -- as they looked for the most practical route. This was the most gruelling terrain they encountered on the entire trip and it was their introduction to the north-west. At this point they met with Shoshone Indians to trade for horses and found that Sacagawea, the young wife of their French interpreter, was a sister to the chief. She had been captured as a young girl and now returned home as a member of the expedition. Chapter two describes another dramatic event involving an Indian woman, the Nez Perce Wetxuiis, who was never mentioned in the journals of the expedition, but who may have saved the lives of the starving and exhausted white men. The Nez Perce proved to be stalwart friends who shared food, knowledge of the country, and dugout canoe construction so the Corps could continue on toward the ocean. Chapter three focuses on reaching the Columbia River, the Big River, a critical milestone that they hoped would take them swiftly and easily to the Pacific. They met more friendly tribes there and joined them in feasts of salmon. Chapter four describes the explorers encounter with the Chinookan Traders at Celilo Falls, the Great Falls of the Columbia, where they entered yet another world in the culture of Northwest Indians. Here they were faced with the sophisticated centre of trade for the Pacific Plateau Trade System. Tribes from downriver came to trade and meet with those from the eastern plateau region of the north-west. The Corps entered the spectacular Columbia River Gorge, navigated dangerous rapids in dugout canoes and survived to continue onward downstream. Chapter five covers a gruelling 150 miles downstream from the beginning of tidal influence to the Pacific Ocean. Battered by storms and tides, this relatively short distance was anything but a downstream float trip. However, they did plant the flag for the United States on the northern shore of the Columbia River, near the ocean, and thus staked a claim to the north-west. This done, they immediately made plans to pass the winter in a sheltered spot on the south shore and made their way across the river to build a stockade they called Fort Clatsop. The winter passed there is covered in chapter six. They brought journals and maps up to date, hunted, made moccasins, and traded with their Indian neighbours. Chapter seven is an account of their homeward journey east -- now up the Columbia. They portaged around rapids and, finally, took an overland route to the lands of the Nez Perces. Chapter eight describes their reunion with their Indian friends and their stay with them while waiting for the snow to melt enough to open Lolo Pass for their last crossing of the Divide. The book ends with an epilogue and brief profiles of Captains Lewis and Clark, the Shoshone woman Sacagawea, and York, Clarks slave. Each chapter contains a trail guide which points out actual sites of camps and significant events and landmarks experienced during the expedition. There are also regional places of interest and sightseeing opportunities listed, along with maps. One of the directives given to the Captains was to collect information on flora and fauna that might be new to science. They did so with great scientific care and skill. At the end of this book you will find a description of the plants and animals the explorers catalogued as they travelled across the north-west. There is also a bibliography and an index.