Book excerpt: Popular historian D’Arcy Jenish recreates the adventure and sacrifice of mapmaker David Thompson’s fascinating life in the wilderness of North America. Epic Wanderer, the first full-length biography of David Thompson, is set in the late eighteenth and early nineteenth centuries against a broad canvas of dramatic rivalries—between the United States and British North America, between the Hudson’s Bay Company and its Montreal-based rival, the North West Co., and between the various First Nations thrown into disarray by the advent of guns, horses and alcohol. Less celebrated than his contemporaries Lewis and Clark, Thompson spent nearly three decades (1784–1812) surveying and mapping over 1.2 million square miles of largely uncharted Indian territory. Travelling across the prairies, over the Rockies and on to the Pacific, Thompson transformed the raw data of his explorations into a map of the Canadian West. Measuring ten feet by seven feet, and laid out with astonishing accuracy, the map became essential to the politicians and diplomats who would decide upon the future of the rich and promising lands of the West. Yet its creator worked without personal glory and died in penniless obscurity. Drawing extensively on David Thompson’s personal journals, illustrated with his detailed sketches, intricate notebook pages and the map itself, Epic Wanderer charts the life of a man who risked everything in the name of scientific advancement and exploration.