How did colonial and tropical geography as practiced in the aftermath of World War II become development geography by the 1970s? We excavate the genealogy of development geography, relating it to geopolitical, economic, and social traumas of decolonization. We examine how revolutionary pressures and insurgencies, coupled with the eclipse of formal colonialism, led to the degeneration and displacement of a particular way of writing geographical difference of ''the tropics.'' A key objective here is to complicate and enrich understandings of paradigmatic shifts and epistemological transitions, and to elaborate archaeologies of development knowledges and their association with geography. While interested in such a big picture, we also approach this story in part through engagements with the works of a series of geographers whose scholarship and teaching took them to the tropics, among them Keith Buchanan, a pioneering radical geographer trained at the School of Geography of the University of Birmingham, England, who later worked in South Africa, Nigeria, London, Singapore (as an external examiner), and Aotearoa/New Zealand.