At the beginning of the twenty-first century, potentiality serves as a central concept in the life sciences and in medical practices. This special issue of Current Anthropology explores how genes, cells, bodies, and populations as well as technologies, disciplines, and research areas become imbued with potential. We suggest that anthropologists of the life sciences and biomedicine should work reflexively with the concept of potentiality and the politics of its naming and framing. We lay out a set of propositions and emphasize the moral aspects of claims about potentiality as well as the productivity of the ambiguity involved when dealing with that which does not (yet and may never) exist. We suggest that potentiality is both an analytic-one that has appeared explicitly and tacitly in the history of anthropology-as well as an object of study in need of further attention. To understand contemporary meanings and practices associated with potentiality, we must integrate an awareness of our own social scientific assumptions about potentiality with critical scrutiny of how the word and concept operate in the lives of the people we study.