Radio is the most widespread electronic medium in the world today. As a form of technology that is both durable and relatively cheap, radio remains central to the everyday lives of billions of people around the globe. It is used as a call for prayer in Argentina and Appalachia, to organize political protest in Mexico and Libya, and for wartime communication in Iraq and Afghanistan. In urban centers it is played constantly in shopping malls, waiting rooms, and classrooms. Yet despite its omnipresence, it remains the media form least studied by anthropologists. Radio Fields employs ethnographic methods to reveal the diverse domains in which radio is imagined, deployed, and understood. Drawing on research from six continents, the volume demonstrates how the particular capacities and practices of radio provide singular insight into diverse social worlds, ranging from aboriginal Australia to urban Zambia. Together, the contributors address how radio creates distinct possibilities for rethinking such fundamental concepts as culture, communication, community, and collective agency.