Worlds of Political Economy explores the meanings and workings of political economy as a source of knowledge and power in national, imperial, and transnational settings in the nineteenth and twentieth centuries. Giving attention to the rich and contested social and cultural nature of political economy as a cluster of ideas and working practices, this volume brings together original essays on sociability, philanthropy and self-interest, imperial land and ecology, international development and public health, expert cultures and transnational diffusion.