Temporality is a central constituent in processes involving the mutual coproduction of science, technology, and society. The discourses and narratives ascribing social and technical meanings to new and emerging technologies are often impregnated with simultaneous appeals to the past, present, and especially the future. The early development of nanoscience and nanotechnology was clearly no stranger to these temporal embodiments. This chapter explores how socially relevant or popular narratives shaping the social life of nanotechnology (e.g., Feynman discourses, the Drexler-Smalley debate, institutional support, and funding narratives) incorporated and exploited representations of the future (e.g., expectations, promises, and visions). In contrast to studies focusing solely on the “futures” developed by institutional, scientific, and technical advocates of nanotechnology, the focus here extends to the “futures” mobilized, promoted, and stabilized by humanists and social scientists who have made nanotechnology an object of study, normative critique, and intervention. In doing so, this chapter identifies certain ambivalences. Humanists and social scientists criticized and problematized the promissory rhetoric underlying the promises, visions, and sociotechnical potentials of nanotechnology. Meanwhile, some were enmeshed in, nourished by, and capitalized on the future-based momentum fueling the development of nanoscience and nanotechnology.