This volume interrogates the interplay of knowledge, nature, and value. Emphasizing the relationship between power and knowledge in the production of environmental facts and values, the authors urge us to pursue diverse and often marginalized forms of knowledge as a necessary first step toward a more egalitarian praxis of environmental science. Debates over nature's value tend to pit instrumentalist valuations of nature against intrinsic values, or ethically rich "cultural" values versus ethically empty economic values. The opening contributions to this volume explore how knowledge is produced in creative, plural ways even within what appear to be homogenous domains, and contest the primacy of the market as the exclusive arbiter of value. From the value provided by marine ecosystems to the market in offsets to the dynamics of gentrification, tremendous social labor goes into creating the "natural" force of markets in nature. Like nature itself, the markets made in this domain are deeply social, and sometimes flimsily constructed. By drawing out the creative contingency of socionatural world making, the authors in this collection penetrate the veneer of nature's value to reveal a rich ground for critical inquiry-and action.