Today, the idea that the Himalayas have the world’s tallest peaks—by a large margin—is entirely uncontroversial. Just about anyone can name Mount Everest and K2 as the world’s tallest and second-tallest mountains respectively.But the idea that this mountain range had the highest summits used to be quite controversial. Mountaineers claimed that the Himalayas could not be taller than peaks in Europe or South America, like Ecuador’s Chimborazo. Even when it was proven that the Himalayas were taller, mountaineers would praised the aesthetic quality of European and South American peaks—essentially giving the nineteenth-century equivalent of “height isn’t everything”That’s merely one of the historical details from Lachlan Fleetwood’s Science on the Roof of the World: Empire and the Remaking of the Himalaya (Cambridge University Press, 2022), which studies the first attempts to survey this mountain range. Fleetwood’s book examines not just the expeditions themselves, but also how surveyors procured their equipment, how they handled altitude sickness, and the fossils they found (among other details), in order to analyze the connection between knowledge, the frontier, and empire.Lachlan Fleetwood is a historian of science, empire, geography and environment. He holds a PhD in history from Cambridge University, and is currently a research fellow at University College Dublin. He is currently developing a new project that examines climatic sciences and environmental determinism in imperial surveys of Central Asia and Mesopotamia in the long nineteenth century.In this interview, Lachlan and I talk about the Himalayas, how the first surveyors studied them, and why these early efforts to understand this mountain range are important to how we understand the history of science.You can find more reviews, excerpts, interviews, and essays at The Asian Review of Books, including its review of Science on the Roof of the World. Follow on Facebook or on Twitter at @BookReviewsAsia.Nicholas Gordon is an associate editor for a global magazine, and a reviewer for the Asian Review of Books. He can be found on Twitter at@nickrigordon.