This work "is primarily a guidebook, but it is also history, told ... in geographical rather than chronological or topical sequence. The explorers Lewis and Clark, the fur trader Manuel Lisa, the refugee Mormons, and the construction gang of the Union Pacific Railroad are tied together by campgrounds near the same place on the bank of the muddy Missouri ... When possible the story has been told through extracts from the diaries and other writings of the actors and their contemporaries"--P. xi.