collaboration “If glaciers are what you are after, that’s the place for you.” The speaker was a prospector passing through Fort Wrangell, Alaska, in 1879. The subject was a remote bay, flanked by rugged walls of ice and filled with floating bergs. The listener was the Scottish-American environmental philosopher John Muir, who needed no further encouragement to set out in a canoe soon after with a large stock of provisions, blankets and a determination to visit the frozen wonderland. It was October. Winter was approaching. The territory ahead was largely uncharted. His five travelling companions — four members of the Hoonah Tlingit people and a missionary — were warned the dangers were so great they would never return. Muir was undeterred. “The icy regions burned in my mind,” he noted. “I determined to go ahead as far north as possible.”