In the late 1890s a young man named Charles Leach—along with some friends and about 100,000 other prospectors—traveled to the Yukon, hoping to strike gold. The punishingly harsh conditions and chaotic boomtowns of the Klondike gold rush have been mythologized in fiction, poetry, and film, but Mr. Leach’s letters home deliver an exceptionally rare contemporary account of day-to-day life in the far north. He became the cook for his expedition, and wrote to his wife in rich, transportive detail about supplies and budgets, wild bear steaks, and exorbitant $15 doctor visits. Ultimately, he—like so many others—left disappointed, but arguably the real treasure turned out to be the fascinating first-hand account that he wrote along the way.