David Montgomery is a geomorphologist who looks at the processes shaping Earth’s surface and how they affect ecological systems — and human societies. He has studied everything from the ways that landslides and glaciers influence the height of mountain ranges to the way that soils have shaped human civilizations, both now and in the past. He has worked in mountain ranges throughout the world, from the Cascades in the Pacific Northwest to the Andes in South America and Tibet, and the Himalaya in Central Asia.