During the late eighteenth and early nineteenth centuries, the North West and Hudson's Bay companies extended their operations beyond the Rocky Mountains to the Pacific Ocean. There they encountered a mild and forgiving climate and abundant natural resources and, with the aid of Native traders, branched out into farming, fishing, logging, and mining. Following its merger with the North West Company in 1821, the Hudson's Bay Company set up its headquarters at Fort Vancouver on the lower Columbia River. From there, the company dominated much of the non-Native economy, sending out goods to markets in Hawaii, Sitka, and San Francisco. Trading Beyond the Mountains looks at the years of exploration between 1793 and 1843 leading to the commercial development of the Pacific coast and the Cordilleran interior of western North America. Mackie examines the first stages of economic diversification in this fur trade region and its transformation into a dynamic and distinctive regional economy. He also documents the Hudson's Bay Company's employment of Native slaves and labourers in the North West coast region.