The world we live in has been shaped by expertise. Yet experts were not born with power: they had to struggle to achieve their authority and legitimacy. Experts have framed economic development, the environment, energy, and infrastructure as work in progress, allowing them to put their specialist knowledge into practice. But who qualifies as the right expert for the job? Who decides how expertise is used, and to what ends? This book traces the changing contours of expert cultures, their global diffusion and local resistance. The contributors examine international organisations such as the United Nations, the World Bank, the International Monetary Fund, and the World Energy Council. They show how experts have tried to manage and navigate the competing demands of scientific knowledge, political power, and the public sphere throughout the last century. Amid the unfolding crises of democracy and climate change, this volume offers a timely, critical analysis of the power of experts and its limitations.