During the last three decades, corporations allied with scientists and universities, national and regional governments, and international financial institutions have, through a variety of mechanisms associated with neo-liberal globalization, acted to dispossess large proportions of the world’s population of their commons’ resources and enclose them for profit making. In response, throughout the global South and in the cities of the global North, large numbers of people have formed movements to defend the commons in all their variety. The idea of the commons has thus emerged as a global idea, and commons have emerged as sites of conflict around the world. The essays in this forum assess strategically the situations of selected commons in a variety of diagnostic sites where they exist, the ways in which they are being transformed by the incursions of capital and state, and the ways in which they are becoming the locus of struggle for those who depend on them to survive.