The fur trade was the impetus for much of the exploration and discovery of North America. The essays in Dark Storm Moving West trace three phases of westward exploration: naval and fur trade ventures on the Pacific coast; traders progress along interior rivers and lakes; and the transcontinental Lewis and Clark expedition, which used maps based on fur trade surveys. Author Barbara Belyea poses challenging questions about the rapid expansion, its effects on Native populations, European versus Native cartography, cultural definitions of space, and communication of traditions.